Howdy,
So, I've a '98 XJ, all stock, and a few weeks ago my blower motor stopped working. Was running the A/C, blowing just fine. Went in to listen to some music, came out, fired the engine, turned the controls to A/C, then the fan to 3...nothing. Dead in all four positions. I spent all yesterday and most of today trying to fix it after doing some pretty extensive research. I've replaced both fuses (15 and 40 amp), resistor, relay, and the blower motor itself. I pulled the dash apart, checked the control connections and they look fine - not burnt, seated properly. Only option left is to replace the controls themselves, unless there's another idea to consider. I'm all ears.

I'm also thinkig there is a thread on this already, so point me there - only one i found was titled '3/4 blower speeds'.

 

Have you tried jumping wires at the controls to see if it works then? That would narrow it down to the switch.

 

Oohhh - yeah. I see where you're going with that. I tried direct power from the battery before i swapped the motor, so maybe it's something further up the food chain. How would i get power that far up?

 

Well, there should be power there already with the key on. It goes from the battery through the ignition to the switch and from there to the resistor and then the blower motor. You could use a test light to look for power at the connection and then jump it to another wire with a paperclip or something.

 

Nope. The motor gets the power and the resistor is the ground circuit. The control switch just chooses which resistor tap to ground. It could be a loose ground for the control panel or a bad control switch. Actually, now that I think about it, the blower runs at low speed whenever the mode switch opens the air door, which means the blower speed switch is grounded thru the mode switch whenever it's not in the off position. Could they make it any more complicated?<br /><br />You can "proof" the motor by applying power to one pin and grounding the other. It's a permanent magnet motor so it will run in either direction depending on polarity. The motor harness plug should be hot whenever the key is on for ignition but not on accessory. Then you can check the switches with an ohmmeter for ground in every position thru the resistor plug. AND the wire from the motor plug to the resistor for continuity.

 

Well I stand corrected. you should still be able too jump the wires at the switch and make it run anyway.