2004 CHEVY IMPALA. HEAD LIGHTS GO OUT,THAN COME BACK ON,THAN OK FOR WEEK OR SO THAN DO IT AGAIN, EVERYTHING ELSE WORKS. My GM Dealer Could not fix it. CAN YOU HELP? THANK YOU.

 

Answer: Well, 2 of the two most common problems are a faulty headlight switch, or a Body Control Module (BCM).

 

The headlight switch can actually smell burned when it is faulty, Smells like burning electrical smell. The connector on the back of the switch can also look black and burned. If that were the case, the connector may also need to be replaced. A faulty switch will usually also effect the interior dash, radio, A/C panel lights as well.The BCM is much more difficult to diagnose, especially when it is not acting up. I would assume they scanned it for possible codes, and found none.


I have 2004 Chevy impala and the security light is coming on after I start the car. If the Theftlock is on how do i reset it?

 

Answer: The vehicle is seeing an incorrect reading in the theft system. You need to have the system scanned for codes. Most likely this is a problem in the ignition key cylinder or the ignition switch. Eventually this condition will occur when trying to start car, and it will not start. If you have a non-factory alarm or remote start, they are know for causing problems in the vehicles theft system.


No way to reset system. There is some sort of problem that needs to be repaired. If you run into a problem where it will not start, then you can try to relearn the system, but it will not last. May have to do it each and every time. The way to do that is this...

 

1. Attempt to start the engine, then release the key to ON (vehicle will not start).
2. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
3. Turn OFF the ignition, and wait 5 seconds.
Repeat steps 1 through 3 two more times for a total of 3 cycles/30 minutes (the vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK).

 

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Comments  

 
# Opel 2010-10-23 01:06
I had similar problems like the question at the top. It was on my 2001 Chevy Impala. The car had problems with the headlights, but also the interior lights, the door locks, and also the dash was flickering. Plus there was a whole bunch of clicking underneath the dash. The mechanic replaced the BCM and said that it was pretty common on the Impala. The cost was not too expensive. If I remember, it was about $350.
 

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