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Add rear heat option?

5K views 31 replies 12 participants last post by  Rinny 
#1 ·
As I do my 5.7L swap I was thinking about adding the rear heat, I have the rear a/c. I have a nice 2004 I was going to build after I get done with my 2003 but now I am thinking I can remove the rear heat out of the '04 and put it in the '03. I am going to swap out the leather seats from the '04 also. The 04 is a nice van and I will probably sell it after I get done with the '03 and put the '04 back together. Is this a good approach? The '03 is a sweet truck and I have a lot of time and components in it. The underneath and the front end are all redone and it is lifted.
 

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#2 ·
Rear A/C is not related to rear heat.

To add rear heat in a non rear heat van would likely involve -

- Physically mounting the rear heat coil and blower assembly behind the driver's seat

- Plumbing the hot water lines (2) from the octopus valve to the rear. Probably requires a new/different octopus

- Adding controls to the dash to control the rear fan and the rear water valve

I'm thinking the controls on the dash would require the most creative thinking. The other stuff seems reasonably straight forward. Seems like a pretty major mod.

I suppose if I lived in Minnesota or Moose Jaw Bay or Ice Station Zebra and I regularly hauled people around in the back of my van, I'd consider it pretty important and worth the work.

Lump
 
#3 ·
80 degrees here in South Florida this week... I can't relate. :cool:
But I do use my rear A/C daily.
Except when it dips down to the 70's... then I open the windows.

I don't even have the front heat hooked up in my 92. I bought a new valve and new hoses to hook to the V8... but never did since it's just not worth the trouble for something that NEVER gets used! :mrgreen:

I'm surprised you have rear A/C but not rear heat. My 2000 has both...
I would have thought they were a "group package".

Good luck... stay warm!
Hope this helps!



PS: You're full sized spare on the roof luggage rack just gave me an idea for my next trip!
It just didn't hit me until now... Thanks
 
#5 ·
My suggestion would be to find a system in a auto salvage yard and pull the whole thing. Never strip parts from a good running van you may sell. But to make it easier you could use your other van to learn how to remove it and all that - kinda like an onhand school lesson.
 
#6 ·
I love my rear heat but it gets pretty cold in OH, it was one of the main things I looked for when looking for an Astro, that and rear AC.
The rear heat makes the van warm and toasty like RIGHT now!

I'm not sure how involved it would be to swap over but if you did it and got it to work you will love it.
 
#7 ·
PS: You're full sized spare on the roof luggage rack just gave me an idea for my next trip!
It just didn't hit me until now... Thanks

I am going to mount it on the rear door but I have to build the bumper that allows the door to open and also allows the hatch to open. I just stuck it up there for now. I think it made my roof rack leak some though. All going to be done on this V8 swap. I should be rolling again the end of march, not cutting any corners and everything is getting painted and coated as I do the swap.
Now I am going to Look for the rear heat system out of a junk yard or some one that took it out cause they didn't want it..
 
#8 ·
Rinny said:
I just stuck it up there for now. I think it made my roof rack leak some though...
Hmmm... I hadn't considered that, and I certainly don't want any leaks (we get a lot of tropical rain in Florida). Not sure how sturdy the "roof rack" actually is... especially holding down a heavy tire. The hold down screws look pretty tiny. The other issue I was contemplating was the added wind resistance... it's bad enough already with the extra lift!

I just kinda liked the idea of two spares... a matching full size 31" spare tire (for the AWD)... plus the regular sized spare.
Ok... back to hanging it underneath (for me).

And back to the heat of the subject!
 
#9 ·
I have considered pulling the rear heat from my '99 (with the cover from the gold '02 since it's grey and the '99 is tan) and installing it into the '00 that also has rear AC. I have both sets of rear lines I bought brand new for the '99 - along with a new rear heater core - and never got around to installing the front set...and I have the tranny out already.

I'd get a new heater valve 'cause those things just don't last, plus grab the hoses and clamps from the '99, then 2 new sets of lines, the heater core, blower assembly and cover with ducts in it. And the switch, of course.

I don't know if I'll ever get there, but I have considered doing that.
 
#10 ·
A minor issue but the final step if you want to make it look good, is to also find or switch the interior panel that has the shape for the heater box & fan. Does a non-rear heat interior have the clips & stuff to make it fit? Just sounds like a lot of work. Got a higher speed for the front heater? cheaper & easier.
 
#11 ·
i haven t got to install it yet , but i have the components to do it , swap the trim for the one with heat , the dash switch wireing goes from switch to main harness under the wheel and then from there to rear heater ( i think connectors at heaters are already there ), will have to drill holes for the hoses , then do like Leeann says , i would probly use 2 T valves at the front heater core and run rubber hoses from there to the rear heater core , just close the valves comes summer time , i do not have all the stock hoses valves and what not , so that makes it easyer ,if you have everything from other van and in good working order you could swap the hole thing , could also take it from a junk van and retain heat in the van you intent to sell ,same work pretty much .
 
#12 ·
As I had the displeasure of pulling everything from a junk yard van to add to my cargo here is a brief overview of what you are looking at.

Here is what you need to get.
The heater box which contains the core and blower. Plan on the rivnuts just spinning.
The lower interior trim which has the vents if you can find one with the vent still intact.
The aluminum lines. Nearly impossible to remove if the trans is still in place.
The two control valves. Don't bother wasting your time trying to pull used ones. Just buy new ones.
The wiring harness. Have fun trying to fish this out of the dash buried under all the ducts. It is separate from the main harness but there is a wire that plugs into the fuse block under the dash. You will have to pull the whole dash out to get to the several screws that hold the harness in place. Buried under all the ducts!
The dash switch. The only easy part to remove.

I have no clue how the vacuum for the control valves is routed as I did not get that far.

The only thing easy about removing the stuff was that I had already stripped out the rest of the interior and the coolant was already drained. The only part of any importance if you are using the aluminum lines is to mount them while the subframe is out. Otherwise use nylon reinforced hose.
 
#13 ·
Rockauto also sells the wireing , when i got the parts for mine the donnor dash was already pretty much outa there . sneak in with a batterie buffer for the riv nuts , i do it for door locks actuators
 
#14 ·
Wow a lot of work!! If I can find one in a junk yard that is what I am going to do. Not going to chop up My '04 it is in too good of condition. Thanks for the info.
That is unless someone has the system out that changed their mind and wants to sell it, long shot but thought I'd ask!!
 
#15 ·
I don't really remember how the vacuum octopus valve works when it comes to controlling the rear heat. Some of the dash controls for the HVAC are not electrical wires at all but vacuum lines and valves. I'm thinkin' the rear heat control may have had a vacuum component as well as the electrical for the fan?

Lump
 
#16 ·
Would anyone have a parts list number for the rear heat option from the front heater core back? Since I have the sub frame out I would like to install the factory lines, the valve body and stub it through the floor in the back. I will also install the switch for the heat seeing my dash is going to be apart for a stereo relocation.
 
#17 ·
Even after living in Maine, rear heat was never needed. My 03 really pumps out the heat from the front heater. Granted I used the rear heat, just to keep it in working condition, but never a necessity even in the coldest times.

Seems like a crap ton of work for very little, if any real gain.
 
#18 ·
AstroWill said:
Even after living in Maine, rear heat was never needed. My 03 really pumps out the heat from the front heater. Granted I used the rear heat, just to keep it in working condition, but never a necessity even in the coldest times.

Seems like a crap ton of work for very little, if any real gain.
a bit of work but I do like having the rear heat. I want to do it in stages. It will be easy to install the lines and the different valve with the subframe out. Also it will not be bad to hook up the switch because I am going to have the dash apart anyway.Then I can look for a used rear heat unit with the grill at my leisure. Just need some parts numbers or a link to the numbers. Cant seem to find one. Thanks
 
#20 ·
AstroWill said:
http://www.chevypartsprime.com for the part numbers.
For the life of me I cannot get anything to come up for rear heat components
 
#24 ·
Man that looks complicated!
If I were to run heat to the rear of my van I'd build it myself. Heater core, squirrel cage fan, hose. and I'd get rid of that useless octopus the heater control valve. I'd build a manifold w/ ball valves like Lump did so in the summer hot water doesn't enter the cab.
 
#26 ·
use an old school bus heater :) , fan on 24 volts maybe ? , any how , 2 T hoses at the front core ,rubber hoses to the back , use the electric seat for juice , relay and a switch on acc .that was my plan, if that makes sence.
.
 
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