InvaderTrax

Now that it's cold, I figured I should start troubleshooting my blower motor. Originally, it never worked on any setting and I just assumed the motor was bad. Today, I unplugged the motor and hooked it to a 12V source and it worked just fine. I tested the plug with my DVOM and settings 1-3 were 0.00V while setting 4 was 0.04V. I got out my light and noticed the resistor was unplugged. As soon as I plugged it in, the fan started blowing slowly, about what setting 1 should be. However, at this point, the key was turned off and the blower switch was off. Turned the key on and all blower switch settings yielded the same slow speed. Pulled the resistor and it looked fine, but it only has two coils instead of three. I don't think that's the problem, but I'm not sure what to check next. How would the motor be getting power with the ignition and blower switch set to off?

waskillywabbit

iTrader: (-1)

Replace the resistor.

:wabbit2:

Pool Playen Bob

this ^ do it. do it now. and feel the awesome control of your blower motor.

InvaderTrax

I tested the resistor in another truck and it worked fine, but I haven't tried another resistor in mine. It's still snowing so I'll probably try tomorrow. What I don't get is how it's getting power when the key is off

Pool Playen Bob

i must have over read that part. its getting a full 12 volts with the key off? something not trying to back feed? if not you'll have to just start tracing wires to see where they may lead up. could have a wire rubbed into another wire robbing power.

InvaderTrax

Went out to try and swap the headlight relay and the blower relay and there didn't seem to be one in the fuse box under the hood. There was a big opening where it could go, but no wires. With the resistor plugged in, the blower gets 12V and runs at low speed. The smaller of the two coils on the resistor glows red which may or may not be normal. I suppose if that relay should be there, then I've got some more work ahead of me to figure out where it went

*edit* nevermind I read a thread that said the headlight and blower relays should be next to each other but Alldata says the blower relay is under the dash by the radio

*double edit* pulled the glove box and removed the blower relay. Swapped it in for the headlight relay and the headlights immediately turned on. Gonna order a new relay

Pool Playen Bob

you'll constantly have 12 volts to your resistor. the speed is controlled by how good of a ground you select it to be. slow being quite alot of resistance. and high being little resistance. so that section will get very warm. and that's why she's en-route with the hvac tubes right after your blower. to keep it cool.

what year of vehicle is this? i won't be much of help but that might help others pinpoint something for ya.

InvaderTrax

It was 12V at the blower, didn't bother checking the resistor. And it's an '86. Tomorrow I'll plug in the headlight relay to the blower to make sure before I spend $10 on a relay