Fuseable Link & High Speed Fan

[JcKore]

Need all your help again guys.
94 Astro Van Engine: 4.3 Vin Z

Behind brake fluid reservoir, is a 4 wire fuseable link I believe. one of these 4 wires controls the power for the heater high speed fan. anyone know which of the wires is for the fan? My problem is, no high speed fan. I go out and giggle the 4 wire plug, high speed kicks in. 3 minutes later going down the road. Fan kicks off. Play with plug, kicks back in. So on and so forth. checked connectors and cleaned plug and receptacle. Same thing. Pulling my hair out..
Don't know much about these fusable wires. Would the fusable wire be bad? Any suggestions on how to fix this would be greatly appreciated. Or am I completely off base on this being the problem? Thanks so much... Jack

[Matrixx]

Hi JcKore
Their are no fusable links showing in the diagrams for your year on the hi speed circuit to the blower motor. If it is only shutting off on the hi speed setting, then the only thing that's located on that circuit is 1 plug-in (from the switch inside to the unit outside),the Blower Motor Resistor located at the top of the blower unit where the 3 wire plug-in attaches to,and Blower Motor. The diagram shows the Hi speed wire as Orange in color. It could be the plug-in, resistor or the blower motor itself.

PS: The color of the wires should be:
-Yellow for the low setting
-Light Blue for medium stiing
-Orange for high setting

Hope this helps.

['cudapaul]

If you are taking about the connector that the four fusible links go to, check the interior of the connector to see if any of the contacts have gotten burned.

[JcKore]

94 Astro Van Engine: 4.3 Vin Z

yes I am talking about the 4 fusable links. Will try to check the connector. it's hard to see as it sits behind and below the brake reservoir.
All I know is when I wiggle or move the connector. Then the high speed on the blower motor will kick on. I have the 3 lower speeds all the time. So i'm thinking one of the 4 fusable wires kicks this blower into high speed. The blower motor, relay and all are fine..

[macinlover]

I have a 94 AWD Astro van, which had the front blower issue you mentioned (intermittent or no operation on high speed). It turned out to be an open circuit at the junction block that the fuse-able links tie into, which is located behind the battery. Over time, I had other circuits open up at this block, and in one incident, the van was completely dead when the key was turned on, but the headlights still worked. My solution was to cut all the circuits loose from this block, and rewire them back to the main power terminal at this block. I got rid of the fuse-able link in the blower circuit, and replaced it with a 25 amp circuit breaker.

This picture shows the location of the terminal block, which is located behind where the battery normally sits. The four wires that where attached to the bottom of this block, were cut loose prior to taking this picture. I installed terminal eyelets on the ends of all these wires, including the one from the blower circuit breaker, then stacked them on the same bolt that the battery feed to this terminal block is connected to, and reattached the nut.


Another view of the terminal block.


This picture shows where I mounted the circuit breaker, which has duck tape over the terminals to insulate them. The location shown, is near the fire wall on the driver side, behind the battery.


My front blower works perfectly now on high speed.

[Big_kid]

Excellent writeup & pix!

Thanks for posting!

[JcKore]

Hey thanks alot I really appreciate it. Could you possibly tell me which of the 4 wires of the fuseable link is for the high speed fan???

[macinlover]

Hey thanks alot I really appreciate it. Could you possibly tell me which of the 4 wires of the fuseable link is for the high speed fan???

Seems like it was the wire on the left most side (passenger side) in the picture, but it's been a while since I had the blower problem, so I'm not certain about that.

[JcKore]

Thanks again, I hate to keep pestering you with questions. But I have one more. Did you replace the fuseable wires with new wire? Or just snip them off the block and and use the existing wire.. Also, where would I purchase the 25amp circuit breaker? Auto parts store? Also, is the wire for the blower, the only wire hooked to the circuit breaker? Thanks again. this has been a great help. I promise not to bug you again. lol.. Jack (JcKore)

[macinlover]

I cut the fuse-able link portion of the wire off, that provides power to the front blower, and soldered on a 14 gauge wire with high grade insulation. I then used heat shrink tubing to cover that solder joint. On the other end of this wire, I soldered an eyelet, which I then placed on the bolt terminal of the circuit breaker.

I measured the current in this wire with the blower motor on high, with a clamp on amp meter, and it is 22 amps. You want to use no smaller than a 14 gauge wire to supply this circuit, due to the fairly high current draw. A 25 or 30 amp circuit breaker that resets after it cools off should work fine. I purchased mine at O'Reilly Auto Parts.

Yes, the wire to the blower is the only one connected to the output terminal of the circuit breaker.

I hope this is helpful.

Mark

[JcKore]

Thanks Mark, you've been a great help! Thank you again for your time and quick responses.. I hope I can do the same for someone else in the future.

Jack

[JcKore]

Hi Mark,
How far down does the fuseable link portion of the wire go down from the plug? is there a noticeable difference look to the wire?

[macinlover]

I'd cut the front blower motor high speed supply wire off at the terminal block, then snip off 3" more inches from this wire, which will probably remove the fuse-able portion. Then strip the end of that wire and solder it on to the extension wire that will connect to the circuit breaker.

[JcKore]

Got it thanks. I think yours is the best and quickest fix that I've seen. And easiest! I'm sure my wife will appreciate it very much. As the van is her primary vehicle.
As the first 3 speeds on the blower are almost worthless! Maybe I should have replaced the blower motorwith an OEM one 2 years ago. The aftermarket one I had installed doesn't seem to be as powerful as the original.

[JcKore]

Got a quick question Mark.
I did the fix today on the last wire to the left per your instructions. Still not working, so I figure that was the wrong wire. I also cut the fuse link on that wire so I guess I have to leave the circuit breaker on that wire. No problems so I guess that will be ok.
QUESTION: If I pull the plug, which I know if the van is runnung it will stall out. Can I turn the blower on high, take a jumper wire from the battery, and touch the pins on the end of the plug to see whivh wire kicks in the blower motor? Or, how did you determine which wire was for the blower motor? Or should I just cut the wires at the plug and with fuse wire intact, and just add them to the hot post?

Also I noticed the right side (drivers) fuseable wire gets quite hot to the touch. compared to the center two wires when the van is running, Is this normal?

Thanks again, your instructions made the change with the circuit breaker easy.

[macinlover]

As long as the high speed blower motor relay is energized when you do your jumper wire test, it should work. You could also hook your jumper wire to the power input post of the terminal block, instead of the battery post, which allows for a shorter jumper wire.

In my case, I used a voltmeter to confirm that there was no power to the high speed blower motor relay contact, then went to the terminal block, and looked for power there. You can use a sharp pin, like dress makers use, to make contact with the wire you wish to test with out removing the insulation, if needed. Push the pin through the insulation, then connect one wire of your voltmeter to the pin and the other to battery ground. All wires on the terminal block are hot all the time. If one is missing power, you found a problem.

I would think it’s normal for the fuse-able link you mentioned to be warm to the touch. If the insulation on this link is in bad shape, I'd replace the link.

[JcKore]

Found the problem Mark.
The fix with the circuit breaker was the correct wire. The problem was with the large blower motor relay next to the high speed relay. By accident I touch the relay and the blower motor kicked in. So for the hell of it, I lightly tapped the relay and the motor kicked off. lol... Tap again and it turns on.. I positioned the relay off the firewall and now the blower runs fine all the time. So back to the auto parts store for a new relay today.. Hopefully it's the relay and not a short in the wireing.. Thanks, Jack

[macinlover]

Found the problem Mark.
... The problem was with the large blower motor relay next to the high speed relay. ...

It sounds like you have zeroed in on the problem. I'm not sure which relay you are referring to though, as there is only one relay involved in the front blower motor circuit, and that is the one that energizes when the blower motor switch is set to high.

[JcKore]

It is next to, and to the left of the high speed relay on firewall behind blower box. It is the large rectangle relay. Mine is black plastic, but the autozone one is chrome (metal).

gpsac27003.jpg

Autozone refers to this relay as Blower Motor relay. Pic above is from Autozone website. If I remember correctly, last summer when I unplugged this relay the blower motor stopped comepletely at any speed. Anyways... This is the relay I was tapping on with my finger...

[macinlover]

Your Astro must have a different relay arrangement from my 94 Astro. The center relay of the three located on the passenger side firewall, energizes when the front blower switch is set to high. On mine, there are no other relays in the front blower motor circuit.