Blower Motor Assistance

Hi all, this is in regards to the 1993 GMC K1500.



About a week ago, we got a foot of snow, and the windshield/wiper tray was completely covered. No big deal, simply wiped the snow off, then cut the fan on, and switched it to defrost. Only, nothing came out. I heard the relay "clicking" every time I increased/decreased the fan speed, but no air came out. I figured, maybe some water got in there, and froze, causing the motor to stop running. Next time I went to use the truck, it worked fine. No funny noises, nice and powerful as usual. Fast forward to today, the blower motor has worked fine until now, I figured last week was an isolated event. Until, I shut the truck off, then got back in about an hour later. The fan wasn't working, again, I heard the relay click whenever I increased/decreased the fan speed, but no air came out. I left it on high while driving, waiting to either smell smoke, or pop a fuse, but nothing happened. After a couple minutes, the blower motor came on in full force, as usual. Any ideas on what I should be looking for? I'm thinking perhaps some corrosion on the pins of the relay? The blower motor doesn't make a sound when running (aside from the normal fan noise) and the air output isn't decreased, which would lead me to believe there is some resistance. I highly doubt it's the motor, but I could be wrong. Anyone else have a similar issue? The one in my old GMC was original, although it squealed all the time when it was running. Man, I miss that truck.

It could be the heater motor resistor.... It is what controls the output of the fan. They are easy enough to check, pull the wires off the motor, grond one end of a multimeter, then find the power side of the wires. Flip the fan switch on, and go through the different speed settings.

batty1214 wrote:

It could be the heater motor resistor.... It is what controls the output of the fan. They are easy enough to check, pull the wires off the motor, grond one end of a multimeter, then find the power side of the wires. Flip the fan switch on, and go through the different speed settings.

I'm with Batty. Sounds like the resistor is dying.

Gotcha. Lets see... Since the blower motor is located on the far RH side of the dash near the floor on the 1988-1994 models, is it just a matter of getting the black beauty cover off, or do I have to pull the dash back to get to what I need?


Also, does anyone know what resistance I should be seeing on the resistor with each fan speed? Or is it a matter of it showing "open" that I should be looking for?

as far as getting into it, it should be under your beuty cover, and the resistor somewhere near the motor..... as for what resistance, im not sure. I would look for a smooth transition level between each setting, in volts...