Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 6 of 6 Posts

·
Registered
2004 chevy trailblazer_ls
Joined
·
2 Posts
Discussion Starter · #1 ·
A REALLY odd problem started this afternoon on my 2004 Trailblazer.

I drove home, shut off the car and went inside the house. When I came back outside, I could hear a clicking noise coming from the TB. I found that BOTH the driver and passenger side mirrors were adjusting themselves to the widest view and then, when hitting their limit they keep clicking and jumping.

It was raining a lot today but its certainly not the first time the vehicle has been out in the rain.

The vehicle has power mirrors but does NOT have power seats, driver memory or the curb view function so I'm 99% sure its not an issue of the mirrors resetting to a different driver position.

If I jam the mirrors around a bit by hand, they eventually stop their auto adjusting but it starts up again if I touch the adjustment knob in the vehicle.

Any ideas?
 

·
Banned
chevy
Joined
·
12,987 Posts
UTTTT ohhhh Ghostbuster time...:cool:

Yea sounds like something is def screwed up......or sticking?
My thought is that if it was the switch sticking it would only be moving one mirror, which ever one it was set for. The mirrors work off of one of the BCM's. Don't have a clue which one though. My first thought is to pull the fuse controlling the mirrors and see if it resets them.:undecided

Roadie will know better if he shows up.:D
 

·
Registered
2003 chevy trailblazer_ltz
Joined
·
4,302 Posts
My thought is that if it was the switch sticking it would only be moving one mirror, which ever one it was set for. The mirrors work off of one of the BCM's. Don't have a clue which one though. My first thought is to pull the fuse controlling the mirrors and see if it resets them.:undecided

Roadie will know better if he shows up.:D
OHH yea BOTH are doing it....hmmm ROADIEEEEE where are u? :O)
 

·
Banned
2004 gmc
Joined
·
26,436 Posts
...ROADIEEEEE where are u? :O)
Just got in from a hard day working on the Roadiemobile front suspension - report in another thread later.

OK, there is only ONE BCM in the vehicle. Power mirrors are each controlled by their respective door modules - DDM and PDM. The switch is wired to the DDM (driver's door module), and you should need to rotate the switch to one side or the other before anything happens. What position was the mirror switch in when they were both moving? The center off position, maybe?

If the control switch were wet and had a bit of salt corrosion on the contacts, that could explain it. Normally, the DDM gets mirror commands from the switch. If it's for the driver's mirror, it just executes them. If it's for the passenger mirror, it sends the command over the data bus to the PDM.

If you have memory seats, then the BCM gets into the mix, but your BCM is likely configured to shut up and not pester the door modules with mirror commands (Actually it's the SEAT MEMORY MODULE that gets involved, but again - you don't have that option so you won't have that module)

I think you should just be able to pry up the mirror switch (item 4) and the DDM (item 7) and disconnect the 9-pin connector at the DDM that comes from the mirror switch. It's a 9-pin in a row connector with only 7 of them used.

If the problem goes away with the connector unplugged, the problem is the switch. Otherwise I think it could be the DDM, but you may also find a way that water got in there and you might need some Radio Shack electronic cleaning spray to clean it out.

Good luck. I might not be checking trailvoy again tonight.
 
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top