85 W150 intermittent heater issue

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crazzywolfie

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hahaha ya i could understand that. i don't know much about repairing the systems but i would guess it requires replacing pretty much all the seals in the system and recharging it if that is the issue with yours.
 
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Brucecmc

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Wolfe, do I pop the fuse out and check across those terminals ??
 

crazzywolfie

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popping the fuse out might make it easy to get a good reading. 1 side or the other should have 12v with the key in the run position.
 
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Brucecmc

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So it doesn't skew the potential problem by removing the fuse, to check across the fuse terminals.
 
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Brucecmc

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Good voltage at the fuse panel. I checked at the blower motor resistor, seems one terminal had 5v and the other 12v. And then there was a single terminal, don't know what it was (see pic)
 

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Brucecmc

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Well that's the resistor. I checked at the connector to this. Like dsexpress said the other day, it might be this sucker. Gonna replace it tomorrow (had to order) and see if it is so.
 

crazzywolfie

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do you know what color the wires were that had power? you can try pulling it out to see if there is any issues with it.
 
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Brucecmc

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I don't know. I was just excited there was power on that side of the resistor.
 

Stewart

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It could be a bad fan switch. I have had many burn out (some melted some). I always grabbed a couple when junkyarding.
 
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Brucecmc

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Wolfie,

You asked which pairs had what voltage. Hers is a pic.

The white/blue are the ones that had 5v
The brown/dark green had 12v

And that single green had nothing. But possibly I did t have it grounded well enuf when I took the reading ?
 

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crazzywolfie

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so you had voltage at 4 our of the 5 wires? for some reason that don't seem right but i would need to check wiring diagrams to say. you can try pulling the resister out to see if there is anything obviously wrong with it.
 
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Brucecmc

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Correct. The 2 pairs of wires had voltage but that single green had none. The resistor is 8 bucks at autozone, so I'm gonna replace it (can't hurt and easy to do) if it fixes it, good, if not I have another new part in the project. Honestly between your suggestions and the Haynes manual, the indications point to this resistor.

Where is that switch that you sent the picture of that may be burned out ? I can't find it (probably because I don't know the fact name of it).
 

crazzywolfie

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you got to pull apart the dash to get at that switch. it is attached to the switch that controls the vents.
 
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Brucecmc

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Oh crap. What is the "actual" name of it ? I wanna see if I can find a diagram.
 

crazzywolfie

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i don't know the actual name of them but they are nearly impossible to find.

you pretty much need to unplug the resister when testing power to it. the white wire should have power to it in a/c, vent, heat and defrost. you should only get power to the tan wire in the max a/c, a/c and vent option.

now even with a bad resister the fan should still blow full power with it in the max a/c, a/c and vent option
 

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Brucecmc

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Can you send me the link to that diagram? I can't read it.
 
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crazzywolfie

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ya that one doesn't expand quite as nice. even on my computer i can barely make some of it out. this one should work a bit better
 

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Brucecmc

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The resistor didn't come in. Have to pick it back up tomorrow. Ughghg.
 
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Brucecmc

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Alright. Wasn't the resistor. Changed out with same results. BUT what I did discover while feverishly mashing buttons, that if I pushed harder than you would expect to have to push, the fan would start blowing. AC, vent, heat and defrost. So, possibly the panel control is dorked up? Another symptom: when I wud press the off button, the fan continued to run until I placed the speed controller to low. Then it wud shut off. And the process wud start over. Mash hard, fan comes on for each control, switched low to high, all 4 worked, press off button, won't shut off, flip switch to low, shuts off. Maybe combo of bad control panel and electrical behind the panel? What's our thoughts on this. Sounds like pulling the control panel out will be a b!tsh.
 

crazzywolfie

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it is possible that the switch behind the control is dying. it is a big pain in the ass to take it out. be very careful with the vacuum lines. worse case scenario you could disconnect the stock plug and run some wires from it to a switch to turn the fan on and off.
 
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