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No Rear Heat

13K views 38 replies 10 participants last post by  bobb789 
#1 ·
I just obtained this Van (2001 Astro LS) and I am solving problems one at a time. As the title suggests the Rear Heater is not working at this time, although the Rear Air seems to be (it's cold now so I can not verify Cooling effects, but the fan starts and runs). As the Rear Air is working I assume I can rule out the fuse under the hood. I removed and checked EVERY fuse under the dash in the main fuse box but found no smoking guns there either. I removed the switch and looked inside, there does not seem to be any indication of failure there either. My first question is are the two switches Rear Air and Rear Heat the same except for labeling - if so I can just swap them and quickly diagnose either a bad switch or rule them out as possible failures. Of course the next question would be what to check next. My next question is replacing the lamps in the main Heater/AC control, the Rear Air Control, Rear Heat Control, and the Wiper Control switches - from other posts it seems to be a rather difficult task, any experience out there?

Although a little off topic, the rear Wiper/Washer does not work either and although I have a Haynes Book the wiring does not seem to follow the same color codes - If anyone has an accurate wiring diagram for a 2001 LS please feel free to chime in.
 
#2 ·
ALPO,

Are you saying that the rear heater blower is not coming on? If that is the case, I would definitely say that you have some electrical going on. As far as the switches go, I do not know for sure if the are the same. Do they have the same connectors? If they do, then it might be a safe guess that they are the same. I could be wrong though...

Next you probably want to locate the wires coming from your switch and trace them to the blower. While doing this, you probably would want to get a current tester and make sure you aren't losing anywhere.

Another thing you can do is remove the blower motor and hook up a ground wire and a hot wire to your battery and see if it works then. basically you want to find out where you are losing current and also see if your blower motor actually works...

I hope this helps. If I think of anything else, I'll be sure to post!
 
#3 ·
Correct me if I'm wrong ( I have a cargo) but isn't the rear heater run just like the front heater core with hot water from the engine. In that case it could be a control valve, a clog or a bad heater core.
 
#4 ·
Thanks for the help. I did not check to see if the Heating Lines were getting warm yet, I figured without the fan that would be useless anyway. In my case the fan is not even starting. The reason I mentioned that the Rear A/C was working is that I believe (using the Haynes Book) that both fans are fed from the same fuse under the hood. Therefore, if the Rear A/C Fan is working the fuse must be good (that eliminates one possibility). Next, I must have read it somewhere in here that someone stated that the two switches (Rear A/c, and Rear Heat) are pretty much the same in design, except for the labeling. IF that is the case I could easily determine switch operability by temporarily swapping them. Lastly, I also figured (from other threads) that even if the resistor bank was failed, the Heater fan should still start in high speed (which according to the Haynes Diagram, bypasses the resistor). One step at a time - easiest to the hardest. Once I can get the fan to work, THEN I can worry about the Hot Water circulation.

I did ask if anyone had an "accurate" wiring diagram specific to the 2001 if nessesary - if not, please feel free to reply with that (mucho gracias). With that I could better chase down where the electrons are either hitting a brick wall or falling out of the wires (Short, open end, etc..) before getting to the fan - if all the above fails. This would also be helpful in figuring out why the Rear Wiper/Washer is not working as well.

In ending - I AM SURE someone might have followed this blurry path before me. If so, be a sport and give me the missing pieces of the puzzle you may have. Seeking out and destroying Electrical Demons is a rough task.

It's not a new Van, it's not what some might call "a man's Van", but it's what I have. I am even starting to like it more and more as time passes, it does everything I bought it for (well not actually yet, in the spring I will be pulling my 18" boat here and there).

Thanks again for all the help!
 
#6 ·
I had no rear heat in my 98 Astro as well. It would just blow cold air. I read around on this forum and found the control valve to be toast. Luckily there is a simple fix of re-routing the vacume lines on the valve so that it is constantly allowing full coolant flow. Then when you flick the rear heat switch you will get loads of heat.

When you look at the valve there is the main vacume line coming to the top, and then a small hose connecting 2 vacume nipples below. when the valve is faulty, it wont allow the vacume to reach the bottom most nipples. if you take off the top vacume line and connect it to the bottom nipple on the valve, it should work. I dont have any picture of the valve, but im sure someone does. I have seen them on here before.
 
#7 ·
The rear heat in my 2001 is a completely different system from the rear air. The 'fan' for the heat is in the panel behind the drivers seat. I'm not sure where it get's it's heat but I'm positive it is a different 'switch'. Also, I believe the rear air actually is ducted from the front but would not say "I'm positive" of that. good luck
 
#8 ·
Someone just had a problem like this, and it turned out he had the connector for the rear wiper in the heater switch. Since you mention your rear wiper doesnt work either thats the first thing I thought of.

Connector for rear heat has, orange, red, dark blue, white, grey/black and black wires. Rear wiper is white, lt blue, grey, dark green, black and grey.

Hope that helps,
Scott
 
#9 ·
BINGO, sfeaver. It was actually a combination of the wiring being switched between the Rear Heat and the Rear Wiper AND faulty switches. After swapping the harnesses the Rear Heat would work on at least the two upper speeds and the Rear Wiper was running - constantly. I was able to fix the Rear Heater switch myself but a quick trip to the salvage yard was needed to get the Rear Wipers working. As I have just obtained the Van I can only figure that the previous owner was working on the issue and simply hooked up the harneeses backwards and sold the van.

Like I had said earlier, baby steps - cheapest first. Now that the Rear Fan is functioning properly I have no heat - just cold air. From all I know the previous owner may have manually bypassed the entire Rear Unit as a result of,.... whatever. I actually did this as a emergency cure to a hose rupture in the past myself. I have a Haynes manual but it gives actually no information as to Rear Heater Valve location or tubing so this will be another task. I did find that Advance Auto has the Rear Heater Valve for $27, but being a cheap skate I figure to give it a going fixing what I have first. I realize from an earlier post that I can move some Hoses around and constantly have hot water running through the system (which I am considering) but would like to have it functional normally.

Sooooo, if there is any further advice - keep it coming, AND thanks for all the help given so far!

By the way on the Fuel Vapor odor and the po440 OBD code issue - I have found that immediately after filling the van I get the odor AND at times the van will have a SERIOUS MISS at idle (but only at idle). The problem (and odor) quickly go away as the tanks empties. Just in case someone has any ideas. (I will add this to my other post later).
 
#10 ·
BINGO, sfeaver. It was actually a combination of the wiring being switched between the Rear Heat and the Rear Wiper AND faulty switches. After swapping the harnesses the Rear Heat would work on at least the two upper speeds and the Rear Wiper was running - constantly. I was able to fix the Rear Heater switch myself but a quick trip to the salvage yard was needed to get the Rear Wipers working. As I have just obtained the Van I can only figure that the previous owner was working on the issue and simply hooked up the harneeses backwards and sold the van.

Like I had said earlier, baby steps - cheapest first. Now that the Rear Fan is functioning properly I have no heat - just cold air. From all I know the previous owner may have manually bypassed the entire Rear Unit as a result of,.... whatever. I actually did this as a emergency cure to a hose rupture in the past myself. I have a Haynes manual but it gives actually no information as to Rear Heater Valve location or tubing so this will be another task. I did find that Advance Auto has the Rear Heater Valve for $27, but being a cheap skate I figure to give it a going fixing what I have first. I realize from an earlier post that I can move some Hoses around and constantly have hot water running through the system (which I am considering) but would like to have it functional normally.

Sooooo, if there is any further advice - keep it coming, AND thanks for all the help given so far!

By the way on the Fuel Vapor odor and the po440 OBD code issue - I have found that immediately after filling the van I get the odor AND at times the van will have a SERIOUS MISS at idle (but only at idle). The problem (and odor) quickly go away as the tanks empties. Just in case someone has any ideas. (I will add this to my other post later).
 
#11 ·
OK, moving along with the troubleshooting. First I verified Vacuum at the Solenoid on top of the Rear Heater Control Valve, good. Then using a previously mentioned method (thanks) I bypassed the Solenoid by routing the feeding Vacuum tube directly to the Valve, no luck - still no heat. With the front heat working seemingly as designed I assume the main valve is working correctly so I believe this narrows my search to the Rear Valve. With those cheap, yet hard to remove, factory clips on the hoses I assume this valve has never been changed, HOW THE HELL did you guys replace this valve! I am roughly 6' and wieght 240#, my arms are not skinny and being 50 years of age not as flexible as they once were either. However, just the fear of finding out just how much having this done for me has me edging toward the task at hand (I have done harder things..., maybe). Interestingly enough I do not see a replacement Solenoid listed anywhere. IF I do this I would most definately want to change the set together so that hopefully I would NEVER need to do this again. On the pessimistic side, IF I blindly replace the valve it WILL turn out to be something else (murphy's law kicks my a$$ evertime). So I am also thinking of first using a "Nipple" (control yourselves guys!!) to bypass the valve altogether - if that doesn't work,.... it's time to get out the Ouiga Board I guess.

One more question - In a previous post there was mention of two valves, the one mounted by the Air conditioning condensor under the hood and another by the frame rail under the van. I could not find one under the van, just the under hood valve. I assume that there is only one valve on a 2001 - please correct me if I am wrong.
 
#12 ·
Here are the solenoids from the parts catalog. My guess is the one with the six hoses as seized inside. From what I can remember there should be an arm on one side that you can move by hand? I could be wrong on that though. Feel the hoses and see if it is warm going into the other solenoid that only has two hoses.

This stuff is under the A/C accumulator, if you take off the top fan shroud it makes access a little easier. But its not a fun job at all changing the valve.



Scott
 
#13 ·
Using the Diagram I will try to understand the system (I wish Haynes had this)
Front Heat - Hose 12 feeds coolant from the engine into Valve 16, then dependant on Temp Dial Selection coolant is ported through the valve into Hose 25 (or 26) to the front core and then back through Hose 26 (or 25).
Rear Heat - Hose 13 feeds coolant from the engine into Valve 16 which passes uncontrolled (I'm a little fuzzy on that) into Hose 32 into valve 31, then dependant on Rear Heater Switch position (energizing a Solenoid not shown on diagram, but mounted atop valve 31 allowing vacuum to accuate Valve 31) coolant is ported through Hose 33 to the Rear Heater Core and back through Hose 7.

I do not see how the coolant returns to the engine on the diagram though.

However,...

The solenoid that I was talking about is not illustrated on that diagram. It is mounted on top of part numbered 31. The Main Vacuum Hose feeds into that solenoid and when actuated allows the vacuum to paas through and feed into the valve, which is number 31 on the diagram.

As far as the 4 port valve (16 on the diagram). I am assuming, as dangerous as that usually is, that it is good because it is working the front heating system properly. By that I infer that when I turn down the Heat Dial, the Heat from the front ducts gets cooler - when I turn up the Heat Dial, the air from the front ducts gets hotter. Are you inferring that the valve can be partially working only allowing coolant to the front heater core? I assumed it was a single plunger type valve that was either Open or Shut for both front and rear Coolant flow - the second valve (31 on the diagram) in turn would then allow or prevent flow to the rear heater core.

Now on that thought pattern (if valve 16 controls flow to both cores). If I were to eliminate the Rear Control Valve (Part 31) using a straight Nipple, wouldn't the 4 Port valve STILL Open and Close controlling Coolant flow to BOTH Heater Cores based on Temperature Dial position. That way in the summer when cooling the Van there would be no Coolant flow to either Core but in the winter there would - all the time to the Rear Heater.

As you can see, I am still a little confused.
 
#14 ·
That valve is either open or closed, the temperature dial has nothing to do with that. That controls a motor inside the heater box inside the van. I dont have a manual handy to see exactly what line is what but you should feel the rear lines get warm.. I'll post later with a bit more info.
 
#15 ·
One thing I noticed is the hoses 12 and 13 actually go to the opposite positions on the #16 valve, that diagram from the parts catalog is wrong. Thus Front and Rear means front and rear ports on the valve.

Also one thing to note is the valve doesnt control the temperature. Its either flowing coolant or its not. Temperature is done in the front heater box with a damper and motor.

the Valve (#16) is actually a six-port valve. It has feed and return to the front, the rear, and engine. Hose 32 feeds the rear heat solenoid which should open when the rear heat switch is on anything but off position. I believe hose 33 is the feed side to the rear heater core, but could be the return. I can't remember for sure now that I've come in from the van in the garage :) Doesnt really matter either way though. Hose 12 is where the hot water comes out of the engine, 13 is the return line into the pump.

This six-way valve is controlled by the Max A/C position, it will block off coolant flow into the cores in this position. So you will have no heat if its there.

With the engine warmed up, I am going to assume hoses 25 and 26 are warm as the front heat works. Is hose 32 warm? Hose 33? I have had to replace that solenoid before. If 32 is hot but not 33 thats your problem. You could bypass it, but you would have a hot heater core all the time and would heat the back of the van all the time. And keep in mind just because the solenoid works doesnt mean the valve itself is good.

If hose 32 isnt hot, then I believe that the 6-way valve is bad. I cant remember exactly how it worked inside, but I think it was either open or closed. Closed just made hose 13 go right into 12 and back into the engine.

Hope that makes it a bit easier to troubleshoot.

Scott
 
#16 ·
Didn't gat a chance to work on the Van today, but I am getting a better hold on the flow paths with your last reply. With all the data I have collected I now believe the flow path(s) to be:

Hose 13 supplies HOT Coolant from engine to Valve 16.
PATH ONE - No Heat Selected (Summer)
• This is my weak area, flow is either isolated all together OR is somehow ported directly back to the engine through Hose 12.
(From the pictures I do not see how flow can pass through the valve from Hose 13 to Hose 12 without passing by the other ports (The Valve would have to have some seriously intricate Valve internals). Instead I believe flow is isolated to the front core. I do not think Valve 16 has anything to do with the Rear Core flow, except to eliminate the need for two Tees splitting the flow into two paths)
PATH ONE - Front Heat
• Valve 16 through Hose 25 to Front Core (Modulated by Valve 16, Based on Front Heat Switch Position)
• Flow from Front Core returns to Valve 16 through Hose 26
PATH TWO - Rear Heat
• Valve 16 Through Hose 32 to Valve 31 (Un-Modulated by Valve 16)
• Valve 31 Through Hose 33 to Rear Core (Modulated by Valve 31, Based on Rear Heat Switch Position)
• Flow from Rear Core returns to Valve 16 through Hose 7
Flows from Front Core (Hose 26) and Rear Core (Hose 7) combine in Valve 16 and return to engine through Hose 12.

If this is the case, you are correct - bypassing Valve 31 will retain flow to the Rear Core at all times, therefore maintaining a HOT Rear Core flow even in the Summer - not a preferred condition. IF however flow is isolated in Valve 16 to BOTH Cores in summer when no Heat is Selected (Front or Rear), bypassing Valve 31 would not be all that bad. In the winter even if just the Front Heat running I do not think having flow to the Rear Core would not add too much additional detremental Heat load to the interior of the Van.

I wish I had a spare Valve 16 to look at, without one this is actually quite confusing for such a simple designed system. Maybe someone has one handy that they can look at. One more question - Does Coolant Temp play a part in either Valve position? From what I have seen Valve 16 position is controlled solely by Vacuum fed directly from the Dash Mounted Controls. There is a Solenoid controlling Vacuum to Valve 31 though, although I think that is fed solely by the Rear Heat Switch.

Sorry for the long posts, but this is somewhat confusing. Actually I am stalling getting into replacing the Valve - it does look like a bitch of a job.
 
#18 ·
Still haven't put the new valve in yet, but I did get a chance to look at a 6-way valve. The person at NAPA was kind enough to get one in so that I could look at it. I was right, it has no control over the Rear Heat - in and out. SO, if anyone was to bypass the Rear Heat Control Valve the Rear Core would have flow ALL THE TIME. I guess I will be replacing the valve after all - all it takes is building up the nerve to start.
 
#19 ·
My original symptom: No heat output from rear heat. Blower worked on all speeds. I found 5 problems with my vans' rear heat. 1. Heater core restricted. 2. Rear heater Control Valve restricted. 3. Rear heater Control Valve Solenoid inoperative. 4. Rear heater Control Switch damaged. 5. Vacuum lines broken.
This is a complex system made up of many simple parts. As with any repair attempt, I read the Factory Service Manual prior to diagnostics.
I figured I would start with the simple stuff first and I replaced all vacuum lines because they were collapsed. I checked and cleaned the ground above the front blower motor. Retested and still no heat. With the key on, I unplugged the Control Solenoid located behind and below the A/C Accumulator and tested for power on the Grey/Black wire. No power in any switch position. I verified ground at the solenoid plug and plugged it back in to the solenoid. I removed the heater Control Switch from the dash by pulling the facia panel away from the dash and pushing the switch out the front. I disconnected the switch from the harness and jumped 12V+ to (1596) Grey/Black wire in the connector. This wire powers the Control Solenoid. I could not get the solenoid to click and I knew it was going to be a long day. I removed the upper and lower radiator fan shrouds and the cooling fan for better access to the front and rear heater Control Valves. I left both front core hoses on the front valve and removed other hoses as needed until I had the rear valve free from the plumbing. There are 2 10mm bolts on the front valve and 1 on the rear valve. With the rear valve out of the van I could see a buildup of gunk inside the valve. I used a mityvac hand vacuum pump to hold the rear valve open and flushed it both ways many times. I flushed the rear heater core both ways with a garden hose until clear. A noticable 'plug of gunk' came out on the first flush. I tested the vacuum solenoid with 12V power and ground. There is a '+'(positive) on the side of the solenoid for proper wire hookup. No audible click, would not pass vacuum. There is a 'vent' hole in the bottom of the solenoid and I sprayed some penetrating oil hoping to free it up. Tested it again and it started to work. I think it froze in place from lack of use. I put everything back together and filled the cooling system with straight water for testing. After burping the cooling system and cycling the front and rear controls I still had no heat from the rear heater core! I removed the rear switch from the harness again and opened it up to find a bad contact and melted plastic. I should have found that first but it wouldn't have mattered in my situation. I jumped the Gray/Black wire again with 12V+ and the rear heater hoses started to warm up. At that point I had no blower because I disconnected the switch from the harness but at least I finally had flow to the rear core. I need a new switch. I think the hard part is over.
 
#20 ·
I was reading your post and thought "is that me writing that?" I am not that talented, I'm taking a slightly less direct and organized path. My first attempt was to "bypass" the solenoid by running vacuum directly to the Rear Valve (when I initially pulled the hoses off there was vacuum in the hose) - but this resulted in no heat. I had the system diagnosed by a Dealer and they said the Valve and swith were bad. As I had the Valve and the switch would take a week to obtain I had them replace the Valve (the hard part, I'd get the switch myself later)- as expected no heat, as it still needs a switch. I went home and again "bypassed" the solenoid again - AGAIN no heat, damm. I should have had them flush the rear core and lines out when the valve was out, like you did! It must be plugged, what else could it be! The switch is like $70 so I see no need to get that until I can at least get flow established. Its is like 17 degrees out there now, so working on it myself any time soon without a heated garage is not going to happen. I'm thinking that simply removing the Rear Core and checking for pluggage there might be easier than taking the Valve out again.

If I go back to the dealer I will relate my thoughts on plugging. For all I know the valve and switch could have been good, and they will only replace every piece until they get it working - could get expensive. Then if I take it back and let them replace the switch (finishing "their" diagnosed course) with no success, I will complain that the previous repairs weren't nessesary and it was their faulty diagnosis wasting my money. Any success out there complaining about blind unnessesary repairs escalating repair costs?
 
#21 ·
ALPO said:
I was reading your post and thought "is that me writing that?" I am not that talented, I'm taking a slightly less direct and organized path. My first attempt was to "bypass" the solenoid by running vacuum directly to the Rear Valve (when I initially pulled the hoses off there was vacuum in the hose) - but this resulted in no heat. I had the system diagnosed by a Dealer and they said the Valve and swith were bad. As I had the Valve and the switch would take a week to obtain I had them replace the Valve (the hard part, I'd get the switch myself later)- as expected no heat, as it still needs a switch. I went home and again "bypassed" the solenoid again - AGAIN no heat, damm. I should have had them flush the rear core and lines out when the valve was out, like you did! It must be plugged, what else could it be! The switch is like $70 so I see no need to get that until I can at least get flow established. Its is like 17 degrees out there now, so working on it myself any time soon without a heated garage is not going to happen. I'm thinking that simply removing the Rear Core and checking for pluggage there might be easier than taking the Valve out again.

If I go back to the dealer I will relate my thoughts on plugging. For all I know the valve and switch could have been good, and they will only replace every piece until they get it working - could get expensive. Then if I take it back and let them replace the switch (finishing "their" diagnosed course) with no success, I will complain that the previous repairs weren't nessesary and it was their faulty diagnosis wasting my money. Any success out there complaining about blind unnessesary repairs escalating repair costs?
Sure the squeaky wheel gets the grease. Sometimes though, it gets replaced. Better in my opinion to just fix it yourself. Once and done. No jug-heads from the STEALERSHIP to deal with. Just my opinion. Jim
 
#22 ·
I was hoping you would check back which is why I posted to your thread. The reason I ask this next question is because it happened to me when I had my valve out for testing. When you are bypassing, does the vacuum hose fit snug on the rear heat valve nipple? One of my hand pump test hoses fit the nipple but it turned out it would leak down pretty quickly because it wasn't sealing. Next, are you sure the cooling system is filled completely? I ask this because now we have someone else that has worked on the van. The rear core looks very simple to pull. I had my panel off last week when I was trying to diagnose the DRLs. There's one screw in the footwell and you have to tangle with the seat belt a bit. The rest of my panel is 'pop off' There are 2 spring clamps from underneath and 2 retention brackets on either side of the core. There may be a couple of other small screws or bolts that hold the flange to body. Plastic tanks on the core so a soft touch when removing the hoses is recommended. The 'plug' in mine was tubular and I think it was lodged on one side of the core. Let's keep in mind we're dealing with 15 feet of tube but the most likely place would be on the inlet/outlet of the core or within 6" of the rear valve. As far as the dealer goes, If the customer complaint was "no rear heat", then you should be given a diagnosis and estimate for repairs to "get rear heat". What did they say when you picked up the van? Did they document on the work order or receipt that the rear heat is still inop and customer declined repairs?
 
#23 ·
Sorry for the slight delay. Yes the vacuum hoses fir tight - when I removed them from the solenoid I found that they actually held a noticable vacumm when the engine was turned off. Is the cooling system completely filled - as far as I know. Radiator is topped off, engine temp is running stable, front heat works fine - what else can I check?

I did pay the $80 diagnosis fee for the rear heat issue, and as per that diagnosis I needed a rear valve and a switch. I had the valve already and as they were already in the engine comparment doing a complete tune I had them install the valve then. They did not have the switch at that time, and reported on the order that I still needed the switch for the rear heat to be fixed. I figured the switch being an easy fix I would do it myself later, but before I ordered the switch ($65) I would bypass the solenoid to verify no other issues. The system is pretty simple in design (not in actual ergonomics) so from there I now assume blockage. Of course it could be a defective valve (dread the thought) too.

Now that it has been back for a week there are other issues still plagueing the van. On Friday it snowed AND I filled it up, AGAIN the van developed a serious miss causing the engine lamp to flash. I covered this in a thread elsewhere. I also have a tinny rattle from under the van - they removed the fule tank to seal a leak during the initial visit. I also found a loose vacuum line (disconnested at both ends) under the hood when I got it back. Needless to say It will be making a return trip to find and connct the vacuum line (free of course). They ordered the switch (no money out of my pocket) and intend on finishing the Heat repair. That is where I am at, waiting for the part to arrive. I feel that I need to tell them I bypassed the solenoid a proved that the switch (while maybe being bad) is not the entire issue. I do not want to replace the entire van piece by piece trying to get the rear heat working either. THIS WAS SUPPOSED TO BE A CHEAP ENDEAVOR!
 
#24 ·
Well here I am - the switch has been replaced and still no heat! Now the dealer says the rear core is plugged. Well I had it up to (#*$%) with the dealer, so I ordered a new core off Ebay myself only to find the installed one clear when I removed it. I had a radiator leak so I figured now was the time to combine both jobs while the system was drained. The radiator replacement was actually easier that I thought! Back the &*%$% rear heat, I will remove the valve and try to blow out the lines. If the lines and core are clear, I will check the valve again, possibly defective even though new. By the way I bypassed the vacumm around the solenoid directly to the valve (seems like there was vacumm in the lines), eliminating the possibility of a bad solenoid. On any other vehicle this would be easy (well not easy, but EASIER). I am seroiusly thinking of putting in a manual valve for the rear heat, but I hate bastardized vehicles - this should be easy to get working, it's not brain surgury or rocketry damm-it. All the while I am still having stalling issues in wet/damp weather - I'll get to that after I get the coolant/heating systems fixed. Well off to Walmart to buy a new work light - these things break easy, a little tap and they blow out. I am always open to more suggestions.....

If anyone wants to know a dealer who rebuilds a system part by part until a problem is corrected, I can tell you. I am extremely dissapointed with there methods of diagnosis.
 
#25 ·
ALPO said:
seems like there was vacumm in the lines
??? Is there vacuum?
Sorry to hear all this trouble you're having. Even though the valve is new, it could now have a buildup of gunk. Just check it out when you flush the lines. As far as the work light goes, are you using rough service bulbs?
 
#26 ·
OK, new update. I took the front of the van apart again to get to the valves. I removed both valves (broke the main valve in the process, another $45). The lines were verified clear. I did take more time studying the valves though. It appears that the Rear Core Valve (the one I bought a while ago and had the dealer install) actually uses the vacuum to CLOSE the valve! I could swear I read numerous times in this forum that the Vacumm is ported to the valve (via the solenoid) to open the valve. There was talk someone actually bypassed the soliniod getting the rear heat to work- that's where I got the idea. Although I had the solenoid bypassed for the last few days, it was properly aligned after the dealer work when it wasn't working. The only thing I can think is that it is EXTREMELY hard to vent the rear heating system. When the new valve should be here tomorrow morning, I'll put the whole shebang together and see what happens. I would love to force the fill with the garden hose but temperatures are expected to be in the 20s on off during the week - too risky. If someone could verify the Rear Heater valve operation (Vacumm to open or close) I would appreciate it - maybe the one I got was assembled wrong (long shot). If there are ideas on proper venting I would greatly appreciate it, I have read placing the van at the most possible incline (nose in the air) would help. Well looking forward to attaching ALL THOSE HOSES and there are a lot, and hopefully getting heat. To think I still have that stalling problem to deal with (stalls in wet/damp conditions). Have nice day ya'all.

By the way, I will be leaving the vacuum hose OFF this time (but plugged).
 
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