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Interior lights blinking randomly

17K views 12 replies 6 participants last post by  Jewel red 5 
#1 ·
I have had this problem for a few day with my interior lights blinking when the car is on or off. Tonight after the car had been parked for a while I was taking the trash out and noticed the interior lights blinking. I have replace both #4 and #40 fuses but nothing changed. I also noticed that the body control module was hot to the touch. Could the BCM be going bad? I don't really think it would be a loose connection because even when the car is sitting still it happens but I could be wrong. Is there anything else I can check? Oh, and the last time I did any work to the truck was about a month ago and that was changing the oil so it shouldn't be anything that I have done.
 
#4 ·
The early vote is for a new BCM; but before you do, take a look at the input for the lights.

If they are all flashing, I'm going to suggest it is the dome lights (courtesy) that are flashing.
One switch turns on all of the dome lights; where as, the reading lights have switches at each lamp.

The headlight switch and the switches signaling the 2 rear doors open are hard wired to the BCM.
The 2 front doors and the liftgate signal an open door condition on the data bus.

What I'm thinking, is an open door condition, in combo with the BCMs desire to turn the lights off after a 20 minute period (to save battery power) could (maybe) cause the lights to flash.

The testing, however, is a little involved. What is your ability and experience?
 
#5 ·
I am no mechanic but I do know my way around a car. I also have 5 years experience as an avionics tech, so I know my electronics.

I would like to make sure it is the BCM before I have to buy a new one and spend the money to have the computer reflashed as well.
 
#10 ·
Interior lights flashing

Good Morning,

I was sitting in my 2008 Trailblazer this morning listening to the radio with the truck off when all the interior lights flashed 3 times then stopped. This is the first time this has happened. The one thing I noticed was I had the light switch for the headlights in the off position not in the auto or turned on position. Could this have caused the interior lights to flash.

Thank you,
Rick
 
#13 ·
Just a shot in the dark but I was replacing the rear license plate bulbs with led ones and had the truck off. I turned on the parking lights and raised the rear gate while I worked on it to see if the bulbs were on that I replaced in talking to my friend I guessed the truck timer for the run down protection was up and the interior lights flashed 3 times then all shut off. Maybe the light switch is bad on your trucks not sure how the system works tied into the run down protection. Good luck
 
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