Front HVAC blower problem

[jlatenight]

Hey guys, need some help here. The Front Blower Motor in my '08 Tahoe was spinning intermittently for a while, so I figured I'd try fixing it. When I turned the fan speed knob, it would change speeds, but the fan was not spinning consistently. it was almost like there was a bad connection on the fan or something. I took the fan out and checked the connection. I put my volt meter to the relay side of the connector and turned the knob to different speeds and the voltage changed, so I assumed (maybe incorrectly) that the relay was ok. Plus the fact that, when the fan did spin, it would spin at different speeds. I plugged the fan back in and played with it while unmounted and it seemed like, if the motor wasn't spinning at the time, if I tapped the side or bottom of the motor it would spin or spin more consistently, so I assumed (again maybe incorrectly) that the motor was dying. I bought another one from Amazon (not OEM, so about 1/2 the price) and it was working for a few weeks, and now......nothing. I turn the knob up and down and the motor doesn't spin at all....totally dead.

So where do I go from here? I'm thinking either the new motor went bad, or the relay was the problem the whole time and it finally gave out completely. Maybe it's a fuse? What's the best way to confirm that? If I plug my voltmeter into the relay, what should I see? What voltage should I apply to the motor to test whether it's working correctly?

As always, thanks so much for your help. This site has probably saved me thousands in repairs over the years by now!

 

[jlatenight]

I have to bump this....it was pretty cold driving to work in 12F weather w/o heat

 

[2011SSVHOE]

take the blower out and bench test it put 12v to it see if it works. use a test light or volt meter on harness to check for power.

 

[Vernon Davis]

I am having the same issue on the highest fan speed setting. The blower is intermittent. I have replaced the blower and resistor and the fan at the highest speed continues to be going fast and slow. And at some point and sometimes the fan will stay at the high setting. So not sure if its electrical or the HVAC control.