2020 3.0 Duramax, tow mirror functionality question

[AlexB]

I ordered part 84776100.  Are the blinkers and the side light things supposed to work?  What about when the lights are on at night,  do the marker lights stay lit?  None of that works.

[Sir Dan]

The dealer usually needs to reprogram the BCM if you add electrical options which your truck wasn't originally equipped with.

[AlexB]

52 minutes ago, Sir Dan said:

The dealer usually needs to reprogram the BCM if you add electrical options which your truck wasn't originally equipped with.

Looks like they didn't install the harness. Lol.  Parts will be in next week.

[redwngr]

With factory install, (mirrors/harnesses/programming) the amber lights in mirrors should be on whenever the marker lights are on.

They will blink with the blinkers.

 

The rear facing lights depend on the setting, but they work with the cargo lights. (OM has details, but setting is changed by repeated cargo lamp button presses) 

 

The older type trailer mirrors had red arrows on the glass (and lots of complaints about them) but the T1 version doesn't have them.

 

 

[monteholic]

after you install the harnesses, you still need to take it to the dealer to reprogram the BCM, you should have received a code with the purchase of the mirrors

 

[stewartzach117]

Does anyone have the part numbers to the door harnesses required for the tow mirrors?

 

Thank you,