On my 89 the supply voltage wire/connector went bad some years ago.
American Motors never became proficient in wire harness design and applications, Chrysler made some improvements but did utilize all old AMC inventories and designs for some time.
My blower would fail intermittently, and wire wiggling soon looses it's thrill in cold weather.
Ran a new feed wire of 12 ga, the factory wire is lighter, and a new ground. Also second ground direct to the inner fender close to the blower (never enough grounding on the old XJ's).
Eventually the motor failed and the new unit bolted in and no problems.
Insure your power supply and grounding are good. Run new wires where necessary.

 

Yeah I've ran a few extra grounds to help her out from what I've read. I'll try running a new output wire for the blower. I'm assuming it outputs from the resistor pack?

 

Anyone have a wiring diagram?

 

so that proves ther is something open between 12v and the motor.
what else is there? u r close.

 

I don't have a '92 diagram but the 90/94 diagrams are nearly identical, except the wire colors. 93 is the same as 94. Maybe you can figure out what you need from these diagrams.


1990 HVAC Blower circuit:



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1994 HVAC Blower circuit:



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It has to be in between the resistor and blower motor then. I have different voltages at the resistor for different speeds.

 

thats the first one ive seen with resistors on the 12v side!, usually on the ground side.thats why i couldnt understand what was going on.
one more guess. you should have 6-12 v on resistors with speed setting. nstill sounds like sw contacts ??

im out gotta go play with o2s removal, got a nice shiny wrench...

 

The design changed in 1997 to ground control. Probably because of flyback voltage from the blower motor which burns up the blower speed switch.


As in...



.

 

yeah thats what im looking at sorry.
some cars use a relay for top speed,probably why switches go bad with high current on high.

 

I can't figure this out, it's driving me insane. I jumped the green wire at the resistor to at the fan and it didn't work, so its not losing power there. I really don't want to pull the damn dash apart again.

 

Just took apart the selector switch, cleaned, sanded lightly and regreased. Made no difference. Bout to scrap this hunk of ****. Looked under the dash and don't see any burnt or damaged wiring.

 

Just to be clear, are you saying you installed a jumper from the resistor block, and to the blower motor and the blower still won't work?


How did you get this jumper wire to connect with the blower? Did you also have a jumper wire from the blower to ground as well?

 

Yes I installed a jumper wire from the resistor pack to the blower motor. I also jumped the ground.

Also found out that I do not have power at the resistor, when it's plugged in. I have power at two of the resistor wires while unplugged. The moment you plug it in, the power disappears.

 

Tried bypassing the blower motor fan speed switch, same thing. Has 12v, I jumper it and lose 12v.

 

1st question is, is the diagram below the same as your Jeep?


If so...


If you are losing power at pin "D" (Yellow/Brown tracer wire) at the resistor when the speed switch is set to LO, when plugged in, the problem should be upstream of the resistor, excluding the speed switch - either at splice C43 or inside the A/C Mode Selector Switch, from pin "E" on the mode selector.


Is this your system (wire colors)?



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