Another AC thread, aka; Its getting hot in here

[YukosaurusRex]

Hi all. Tldr version, 05 Denali, with the ATC. Front blower motor stopped. Pulled the blower, turned on the truck and the motor is jerking forward maybe a 1/4 turn. Pausing, then jerking another 1/4 turn, etc over and over. Checked power at full blast at blower plug and got a steady 12 volts. I figured bad blower, picked one up and tried it with the new one and get the exact same thing. 1/4 turn pause repeat. Fuses checked out, couldn't find any obviously bad wires. Any body got an idea on further testing? I've never been the kind to just throw parts until fixed, but I've never messed with a ac system like this one either. Thanks to anyone with advice!

 

[Doubeleive]

blower motor resistor, it's the part the blower motor plugs into, 12v doesn't mean diddly if it has no amperage.

 

[YukosaurusRex]

...I did not even check amperage. Any idea what that number should be? Only thing I read about it was that it should have 12v at the blower motor if the resistor was good.

 

[PG01]

Like wes said, resistor first.

 

[YukosaurusRex]

So, just to wrap this up if anybody searches for similar issues. Ordered a resistor online, took 2 weeks to get here cause fedex sucks. Anyway, mine had never had the new style upgraded type where you have to change the harness too. It fixed it completely. Thanks guys!