Need guidance on new electrical gremlins

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
My 07 TB is currently at 110k miles. It has recently started to show some electrical issues and I am looking for guidance on what modules I might need to start checking into.

The first issue is when the front passenger door opens. The cabin lights turn on but immediately dim and turn off. All other doors cause the cabin lights to operate correctly.

The other issue is with the radio and it just surfaced this morning. When I parked at my office, I turned off the car, removed the key and opened the drivers door. The radio stayed on. I shut the door and when i reopened it the radio turned off. I have an aftermarket radio so I will start with the adapter for the BOSE system/door chime but from there, what should I look at? Edit: This is intermittent. Repeated a few times then functioned as normal with radio turning off immediately upon opening door. BTW...how does the car know the door is open? Is it a switch in the latch?

DDM and PDM? Do these have a history of wire insulation failures similar to the LCM?

TIA!
 

Blckshdw

Moderator
Nov 20, 2011
10,665
Tampa Bay Area, FL
First, and easiest module to troubleshoot is the DDM. Swap it with the PDM and test the same scenarios with opening your door. If the problem flip flops, then obviously you know your DDM is on its last legs.

If the problem remains with the driver's door, next suspect would be the door ajar sensor. I've never dug that deep into my doors before, so I can't tell you exactly where it is and how to get to it, but it would be feeding a bad signal to the door module, and not telling it the proper state of the door.

You could use the wiring diagrams from the manuals in Mooseman's thread to trace the wiring from the DDM if needed. :twocents:
 

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
Thanks. I'll look into swapping them this evening if it doesn't rain. Is it as simple as popping out the switch panel or do I need to pop the door panels off?

Looked at the wiring diagrams for the lock system. Appears the ajar switch is within the latch. Guess I'll have to tear into the door at some point if this persists.

Also, opening the passenger door before didn't replicate the cabin lights dimming immediately.
 

Blckshdw

Moderator
Nov 20, 2011
10,665
Tampa Bay Area, FL
Any flat bladed tool should be good enough to pop the door modules from the door panels. They are held on by clips. Mine have been removed enough that I can do it with my fingers.
 

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
Add in the warning chime continuing to beep after turning on the parking lamps to check my tail lights (was told i had a bulb out by coworker) with door open and key not in ignition, turning off parking lamps and closing door.

Really odd sudden appearance of electrical problems.
 

Blckshdw

Moderator
Nov 20, 2011
10,665
Tampa Bay Area, FL
All of those symptoms point to the same problem, so you should be able to solve all those things at once, after you troubleshoot it.
 

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
Update: Haven't been able to ID the problem here. It's so intermittent and isn't a back-to-back repeated problem that I never get an opportunity to swap the modules and see if it resolves. I don't want to be driving around with switches just hanging out on the wrong door either. I can deal with it. Just have to open a different door and radio turns off.

New problem, which I hope is related to this and is potentially tied to the ignition switch is the HVAC not changing speeds when the car is cold using either automatic or manual adjustments. seems to resolve itself once the car has been run and I presume the switch had warmed up, car shut off and restarted shortly after. Today it also didn't turn off right away after i turned the car from on to acc (hence my belief it's the ignition switch.) FUN!
 

Blckshdw

Moderator
Nov 20, 2011
10,665
Tampa Bay Area, FL
To recap, the passenger side door messes with the dome lights, and the driver's door messes with the radio?

For your HVAC, I would suspect a loosened ground at the bottom of the radio stack on the passenger side, behind that flap of carpet. If it was your ignition switch, I think you'd have some other odd symptoms.

Any time you have intermittent connection issues, that you can relate to a temperature change, you either have a loosened bolt/nut or a broken wire in the circuit.
 

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
I haven't seen the passenger door/light issue since I posted this.

The drivers door/radio/chimes issues is intermittent and I can't figure any external factors that trigger it so I haven't tried swapping the modules.

I am going to check the ground bolt as well.
 

Ziggy

Member
Feb 8, 2015
207
I'd say that the most suspect component to be the cause of your radio/dome light issues is the left front door ajar switch. At the risk of simply throwing parts at it, I'd be inclined to go ahead and buy the latch and have it on stand by when the issues start to present themselves again. Worst case, you end up with a new door latch in the door that you're going to need eventually anyway. I do miss the days of simple plunger type switches in the door jambs...
 

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
Had time and the weather was b-e-a-u-tiful today, so I gave a look into the common ground for the HVAC issue. Everything was clean. Any other possible ground issues that might cause this?

Also, putting the car in park causes the HVAC blower to come on full blast and it won't turn off when the car turns off. This happens totally random. Takes a few starts/offs to get it to turn back off.

Could the aftermarket radio harness be causing the HVAC to act up.

Haven't had the dome light/radio issue in a long time.

I guess doing the ignition contact clean-up couldn't hurt right?
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
It could be the radio harness. What brand is it? It's been blamed for some gremlins.

Definitely cleaning the ignition switch can't hurt. Look for a write up by BlazingTrails. Really good.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
I've had a few of those and the usual problem was the radio staying on and no sound. You could disconnect it and see if it clears up.
 

Blckshdw

Moderator
Nov 20, 2011
10,665
Tampa Bay Area, FL
I've had a few of those and the usual problem was the radio staying on and no sound. You could disconnect it and see if it clears up.

:iagree: I've gone through 3 GMOS units, none worked for more than a couple of months before I started having weird issues.
 

TB_n00b

Original poster
Member
Dec 19, 2011
121
Queens, NY
and upon inspection of the old unit, nothing appears to be wrong with the connectors or the PCB...BUT the heatsink was not longer firmly attached to the FET so I'm going to assume it slowly cooked itself to death.
 

tcurlee

Member
Mar 28, 2015
59
I did a search but couldn't find this exact problem. I have an '05 Envoy 4.2 with stock radio. You know when you turn the car off and before you open the door, the radio stays on for a time as does the int. light. Well, intermitantly , when I turn the car off, the radio and lights go off right away as well. Not a huge problem to have but I guess its a precursor to other problems if left to itself . Any ideas as to what what switch or other item that I could look into?
 
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