Heater Blower Motor Troubleshooting

[slaroche]

I've got a 77 SII w/304 and AC. Ever since I've had the scout, the blower motor would make a loud whining noise when I turned it on. It would eventually go away, but I figured it was just wearing out. So I think it's finally worn out. It doesn't work anymore. I was going to troubleshoot it the other day, but then I saw at least three maybe 4 wires going to it. I know one was a ground, but what are the other wires. Which wires should carry voltage when it's on. Is there a single fuse that I should check. i dont' have my manual with me...it's at home (I'm sure it will be useful in fixing this thing). I'm just trying to get a head start before I go home and start messing with it.

Thanks,
Steve

[jeff campbell]

POKE the wires w/test lite!?don't know,but maybe the other 3 wire's are the speed's?jeff

[BigEddie]

You're right about one of the wires being a ground. I haven't looked at my 76 motor, but my 69's has three wires for ground, high, and low. When I thought mine had crapped out, I pulled the plug and ran the ground wire to a good electrical ground point.

I might get flamed for this low-tech test, but I attached a wire to the positive battery terminal and touched it to each power terminal to check operation. Both terminals made the motor turn, one high, one low. The problem turned out to be the fuse, which is located on the heater switch.

You can do the same to check the operation of your blower motor to rule out fuses or the heater switch. The noise you describe does sound like a worn out bearing or bushing in the motor, which could have lead to a blown fuse. I think you can buy replacement motors at most parts stores, but I have no experience with the quality of the units.

[jeff campbell]

i beleive their pretty much a standard GM motor?jeff