AC blower wasn’t blowing in my son’s 2000 XJ. I could hear the A/C compressor coming on, fuses were all good, and while I know the blower resistor can be a problem, I’d always read a bad resistor keeps the fan stuck on high, not dead. So I figured I had it narrowed to the blower fan. Pulled that today, wired it directly to the battery and it runs fine. SO… what causes a blower not to blow besides a bad blower? Thanks.

 

a bad resistor pack makes the fan only work on High. I'd check the resistor pack anyway and then look at the switch

 

probe the resistor pack with a test light as a first step

 

So the blower does work at all, ac or not?

Check the fan switch on the back of the HVAC control as well as the connector on the resistor.

On high, the resistor is bypassed. On any other setting, power to the fan passes through the appropriate set of resistors to control blower speed. If the resistor burns out, the only circuit left is high. The resistor burns out due to the high current running though the circuit generating heat (why the resistor coils are exposed and does not have a cover). This heat can also damage the connector at the resistor and/or the fan switch in the control head.