What did you do to your NNBS GMT900 Tahoe/Yukon Today?

Fless

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Fuse was missing. I replaced it but still no dice. I hear the relay kicking in and I have power through the fuse. Guess I'm gonna have to check power in the door harness at the mirror switch and compare the plug on the new mirror to the old one I saved. And check wire colors etc.

You're turning the defroster grid on, right?
 

89Suburban

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You're turning the defroster grid on, right?
Yeah bottom button to the right of the power button on the HVAC panel.


Old mirror plug on top, new one on the bottom. Same number of wires in same positions. Colors are different, but I believe the functions are the same regardless. I test plugged in the old mirror and that won't heat up either. I opened that mirror up on the bench and did some tracing with a ohm meter. The black wires on BOTH plugs are definitely for the heated glass. I am afraid to go prodding around the door lock module with test meter probes.




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89Suburban

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yeah I dunno wtf is going on here fuse is good, relay good, rear defrost button is lighting up. Still no power reaching the heated mirrors. I am wondering if the door lock control I replaced isn't programmed for it maybe?
 

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