2003 Trailblazer LZ backlit window switches

Old Coot

Original poster
Member
Jan 2, 2013
58
Since buying the Trailblazer, I am trying to get up to speed on what is installed and what is not. Some vehicles I have had in the past have window switches and door lock switches that are backlit when the headlights are on. Before I start tearing into the door panels to find out, since I do not see any backlighting on them now when the lights are on, can someone tell me if they are supposed to be backlit?
 

Blckshdw

Moderator
Nov 20, 2011
10,674
Tampa Bay Area, FL
Old Coot said:
Since buying the Trailblazer, I am trying to get up to speed on what is installed and what is not. Some vehicles I have had in the past have window switches and door lock switches that are backlit when the headlights are on. Before I start tearing into the door panels to find out, since I do not see any backlighting on them now when the lights are on, can someone tell me if they are supposed to be backlit?

Yes, they should be. When I bought mine, my passenger door module lights were out. Good excuse to swap some LEDs in there. :biggrin:
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Sometimes dashboard switch backlights and rear door switches, if they fail in groups, can be caused by one of two rear fuse panel fuses used for the dimmable lamp buses. The front door switch backlights are a strange ans special case, and they are dimmed by a digital data message to the door module, so GM could save *one* wire in the door harness. But the side effect is that if the switches in the door module work OK, that proves the data communication and power to the module is there, and a dead lamp can be nothing other than a bad lamp. Downside is they aren't socketed and you have to solder new incandescent ones in that you can get from Radio Shack, and many members upgrade to LEDs and resistors.

As time goes on, you will discover more and more extremely subtle design issues like this. Sometimes they're pleasant surprises. :biggrin: Other times....not so much. :hissyfit:
 

Old Coot

Original poster
Member
Jan 2, 2013
58
Thank you for the info and repair tips. LEDs make sense to me. All I should need to find out is the maximum current of the LED and apply Ohm's Law. Soldering is a piece of cake. I have been soldering since high school. After I sold the barber shop I took a job sitting down all day as a production solderer in a small electronics firm. 3,500 to 4,000 joints ( that's solder joints ) a day in 8.5 hours. I guess I should look up specifications for the original bulbs and see how many lumens they put out, too.

Thanks again!:thumbsup:
 

Old Coot

Original poster
Member
Jan 2, 2013
58
It must be magic!

Thanks to roadie's suggestion, I went out in the garage last night to investigate the lack of backlighting on the steering wheel and window switches. I flipped up the rear seat and removed both covers over the fuse box. Having thoroughly inspected the area I removed the fuses for the drivers door and passenger door and returned them to their sockets. Additionally, I moved the flexible circuits up and down in their sockets a couple of times and checked the backlighing again. Magically they are working. I replaced the covers, put the seat back into position and went to bed.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Old Coot said:
It must be magic!
I can't explain why ANY of that would fix the lights without any other function being dead. It might also have been my remote thought control worked for the first time ever.

View attachment 25777
 

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