Hello everyone.
I have a issue with my heater switch. It's an 89 Cherokee, 6 cyl, 4 wheel.
The old heater blower motor was squealing and the switch would only work on high. I replaced the motor and I bought a new switch. Put it on and it still will only work on high. No low or medium, just high. Anyone have an idea or lead I could go on?

 

Likely problem is melted wire wound resistors or blown thermal fuse in the resistor block. The circuitry in the block allows the blower high speed to keep working in this situation. The squealing bearings in the blower motor are causing too much current draw, usually calling for a new motor.


The resistor block is a diamond shaped unit mounted up into the plenum in front of the passengers knees with two hex head screws. If there is no apparent damage, test the thermal fuse with a meter -- should have 0 ohms resistance. In this case you can replace the whole block or just the fuse.


Let us know after you look at it.

 

Ok, I'll take a look at that tomorrow. I did put a new blower motor in it.
I'll let you know.
Thanks

 

I just went through this today. The little thermal resistor tested open. Then when I pulled the switch panel, the connector on the switch was half melted.
I bought a new switch with a new connector/pigtail off of ebay, along with a new resistor.
Locally the resistor was close to 25 bucks & needed to be ordered...the one I ordered was a bit over 8 bucks shipped..
Is the connector on your switch OK ??

 

I replaced the switch, but not the resistor. The connector on to the switch looked ok. Not melted or looked like it got hot.

 

I bought a new Borg Warner heater resister from O'Reillys today. It was only 16.50 with a lifetime warranty. It works perfectly. I have all speeds now on my blower. Thank you much Pelican and Bill.

 

Hey Jurn. I need to do mine. Do u have a BW part #?

 

My dads old Dakota has been doing this same thing for years. He has a wrench next to his seat and he just smacks around under the dash til the fan speed he wants works. Seems like a logical fix.