So my blower motor went out. I replaced it and it worked fine. Two weeks later it died again. !@#$!~ What in the heck?! I haven't checked anything yet, I'm heading out to do that now, just wondeirng if anyone had any ideas. My first thought was the resistor, but the blower motor resistor is used to regulate fan speed. If it went bad by way of lowering it's resistance (approaching a short) then before the fan would burn up with all those amps pushing through it I would have noticed it spinning at a crazy high speed. I guess the resistor could have completely opened on all settings, but that just seemed strange to have these two events happen within weeks of each other. Not to mention, the problem gets a little skecthier. Before the first motor blew it would periodically go in and out of operation. Sometimes it would work, sometimes not. I could flip the switch around, bang on the dash - nothing, then I'd hit a damn bump and it would kick on. I thought... hey, loose connection, duh! Well, when I finally got tired of all this (well after the motor quit working completely) I pulled it out and tested it - it no longer ran. So I just assumed the motor was going bad the whole time.

Check my other threads, I've got an interesting one coming on a wierd problem with my window!!!

 

I checked the resistors - all seem to be okay as long as their values are supposed to range from around 1 to 3 ohms each, depending upon the series combination of the three. No luck there. I'm going to keep tracing it backwards as I have time.... and I don't have time!

 

Pulled the blowre motor out, hooked it up to a 12VDC battery and a 5ohm power resistor... presto, it works fine. Something else is amiss. I'm going hunting with my DVM... be back shortly.

 

DONE! Don't know WHAT went wrong but the motor was fine. I decided to do a quick sanity protector and meter the voltage on the terminals leading to the motor with the switch on, and sure enough 12V was present on high. I must have had a loose connection this whole time despite my attempts to giggle the terminals while attached. My prevailing theory: the ground is attached to the body of the motor housing, which is painted with non-el paint. Perhaps at some point I lost conductivity here. I sanded away until I found some shiny metal and put it all back together.

 

Well, I'm glad you got it figured out and I'm sure that this will help someone else down the road. I didn't reply because it seemed like you were always running in the right direction and when you'd reply with your findings, you'd also list the next step that I would have suggested. Wiring faults are a total pain in the butt and that's if you know what you are doing.

Again, glad you got it figured out and thanks for the followups!!

 

i was having that same problem, but the blower motor was fine so i switched the resistor and it worked for 2 weeks. to begin with it never worked on high, so i replaced the switch. it worked, but not on high. gotta love em'