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sprinkles08, ASE Certified Technician
Category: GMC
Satisfied Customers: 23132
Experience:  ASE Master and Advanced level certified. Factory trained with 17 years dealership experience
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I own a 2007 gmc envoy 6cyl 4x4 my rear defroster does not

Customer Question

hi , i own a 2007 gmc envoy 6cyl 4x4 my rear defroster does not work . iam trying to change the relay for the defroster but cannot locate it . looked at the fuse block under hood and rear seat but no luck . i already did buy the part so it does exist . any help would be great.
Submitted: 1 month ago.
Category: GMC
Expert:  sprinkles08 replied 1 month ago.

Hello and welcome to JustAnswer!

There isn't a relay for the rear defroster. The rear defrost grid is controlled by a driver directly from the liftgate module based on a communication bus message.

A scan tool may be required to diagnose the issue if it's on the input side of the system, but the first thing I would recommend is testing resistance of the heater grid itself to see if there is an open circuit. If ok then the next step would be to test power and ground while the rear defrost is turned on and see which is missing.

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