2016 suburban wiring issues

[o0Nighthawk0o]

A bit of back sorry. My 2016 suburban began glitching just before Christmas 2025. Messages popping up about the airbag, front camera, trailer brake system, among many others. The gauges would reset and, at times, would only click when pushing the start button. Eventually the problem was tracked down to a rodent chewed harness. Mechanic tried repairing the chewed wires but eventually replaced the engine harness.

It's been a week or so now and none of the original problem have come back. But, now there are other problems. The biggest I think is that it thinks the rear lift gate is open even though it is securely shut. Related to this I believe is that the remote start doesn't work, when locking the doors with the fob it doesn't honk the horn like it should, the rear wiper doesn't work and the dome lights stay on unless I turn them off with the switch.

I'm guessing that this is all caused by the lift gate and is a problem with one pin on one plug on the harness that was replaced.


My question is, does anyone know which plug this may be or where I might go to find the information I need? Or am I completely off base that all this is related to the lift gate?

 

[Doubeleive]

I would probably be looking at those rear harness connections a second time and cleaning them with a electronic contact cleaner. then see how it plays out.
occasionally when things are messed with on the k2's a module may need to be relearned but I wouldn't look at that option until everything else has been ruled out.
but I would disconnect the battery and have a good look at those rear connections, clean and reseat.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

Do you have, or have access to, a quality bi-directional scanner? It may be able to help you pinpoint the source of your issue.

 

[o0Nighthawk0o]

Thanks for the welcome. I don't have a bi-directional scanner. Can you recommend a decent one?

Also, thanks for the tips. I'll be checking what connectors I can find and clean and reseat them. My wife just told me that she was driving it and she got the airbag, Park assist and front camera messages again and the gauges reset again. I noticed before that it would get worse if it was damp or rainy and it's been raining off and on here since yesterday. So I think I'm getting moisture in connectors somewhere.

 

[houstontaylor]

The rear liftgate open indication combined with the rear wiper that doesn't work is probably from one of the rear tailgate latches or the window latch. When the computer perceives them to be open, the wiper will not work either.

 

[Hobert]

Thanks for the welcome. I don't have a bi-directional scanner. Can you recommend a decent one?

Also, thanks for the tips. I'll be checking what connectors I can find and clean and reseat them. My wife just told me that she was driving it and she got the airbag, Park assist and front camera messages again and the gauges reset again. I noticed before that it would get worse if it was damp or rainy and it's been raining off and on here since yesterday. So I think I'm getting moisture in connectors somewhere.

Download 2016 Electrical manual here
https://www.gmupfitter.com/wp-conte...Builders_Manual_Service_Manual_2016_en_US.pdf