White plug ignition switch loose wire?

2006 CADILLAC CTS
230,000 MILES • 3.6L • AUTOMATIC
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STRETCH81
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  • 1 POST
On my 2006 cts 3.6l v6 RWD 186,327km Someone had a command start in the car and ripped it out before selling it. Made a mess of the wiring and I’ve cut out all the extra wires hanging around and have one wire left that I can not figure out where it goes.
On the ignition switch I have a green and a tan wire the green runs into the main harness under the steering column and the tan one is just hanging disconnected. It had been tied into the ground previously but I removed it from there.

I am getting security theft light staying on solid I can erase the code but it comes back shortly after, also. Have to temp or fuel gauge.

Codes showing on my Autel MX900

Powertrain
U1300
P0453
P1629

Vehicle theft/security
U1000

DRP/ABS/TCS/VSES
C0278
U1000


VARIABLE STEERING
C0278
U1000

INSTRUMENT CLUSTER
U1000

DASH INTERGRATION MODULE
U1000
B1004

VEHICLE COMMUNICATION INTERFACE
U1000
May 28, 2026 at 1:15 AM
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STRAILER
  • CAR REPAIR CONTRIBUTOR
  • 54,257 POSTS
So the tan (brown) wire has to be connected this is why you are getting all the codes. It powers the dash integration module and the accessory fuse panel. Here is the ignition switch wiring diagrams so you can see where the wire goes and how the system works. Check out the images (below). Please let me know what happens.
Image (Click to enlarge)
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May 28, 2026 at 4:58 PM
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Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.