Over the past year or so my truck has starting eating blower motor resistor packs. The harness looks fine, the connector isn't burned, and the blower seem to work fine, but I've gone through 4 or 5 of them. The ceramic is usually broken and the solder fails. The latest just lost the 2 lower settings. These are new packs from multiple brands. The Mopar units seemed to fail the fastest. Any ideas on where to start?

Thanks for looking.

 

I'd wonder about excessive resistance from the blower motor or bearings. I wonder if you could find a cheapie - maybe on AWD? - to swap in as a test.

I guess you could also check current draw with a clamp, if you knew what it should be.

Finally, I suppose if power is being "choked" that would cause excessive resistance. Maybe check voltage on high at the motor connector? It should be close to alternator output less a bit for voltage drop

 

Thanks Keith. The blower motor was my thought as well. It's original to the truck, so 23 years old. I'm going to check the voltages first, but I'm going to get a motor and resistor pack coming this way since I'm going to need them anyway.

 

Check the grounds as well. Bad ground will give you high resistance too.

 

Sorry, been sick for a couple days. Went out today armed with new blower and resistor pack, and multi meter. It was the blower. The voltages were all close to each other at the relay under the hood, resistor pack and blower. I removed the blower. The wheel was hard to turn. No wonder the resistors were popping. Thanks for the advice. I appreciate it.