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Bulletin No.: 04-06-03-003C
Date: March 05, 2007
Intermittent Dead Battery or Battery Goes Dead Overnight (Replace Overhead Console Assembly)
2003-2005 Cadillac CTS
2004-2005 Cadillac CTS-V, SRX
This bulletin is being revised to update the warranty information. Please discard Corporate Bulletin Number 04-06-03-003B (Section 06 - Engine).
Built Prior to the Production Dates shown.
Some customers may comment on an intermittent dead battery or of the battery going dead overnight.
This condition may be caused by the instrument panel brightness lever, located on the overhead console, being slightly engaged but not enough to turn on the interior courtesy lamps. The slightly engaged switch causes the Dash Integration Module (DIM) to cycle between active and inactive which wakes up other modules on the Class 2 data line. This causes the vehicle to remain active. The scan tool will not indicate that the switch is active.
Technicians are to replace the overhead console assembly with an newly designed part.
The above bulletin is just for your information.
The cause of your issue revolves around the ignition, not releasing the key & keeping the computers active.
Here is another bulletin
Bulletin No.: 05-02-35-002
Date: April 18, 2005
Unable to Rotate Key in Ignition, Ignition Lock Cylinder Jammed (Replace Ignition Lock Cylinder)
2004-2005 Cadillac SRX
Some customers may comment that the ignition key will not rotate in either direction, or that the ignition lock cylinder is jammed.
This condition may be caused by the ignition lock cylinder key guides shearing, causing the lock cylinder to jam when the ignition key is not fully inserted before attempting to rotate it to the Start position.
Using the service procedure published in SI (Document ID #797076), replace the ignition lock cylinder.
Your Basic Warranty is for a period of 4 yr. / 50,000 mi.. As long as you have not exceeded this time or mileage, the repair will be done at no cost to you.
As for cost if you have exceeded the warranty period, it depends on what is wrong
(between $90 & $500)
I strongly recommend the GM major guard extended warranty.