Hardwire Radar Detector
 

I have installed my radar detector above the rear view mirror and wanted an easy way to hardwire it without having to run a wire down the column and have the radar detector automatically turn on and off with the ignition. I have outlined the procedure below:

The below procedure is for 1999-2003 TL without the OnStar System.

1. Remove the front ceiling light.

2. Route the power for radar detector wire along side the wire for the automatic dimming mirror.

3. Locate the 3 prong connector for the automatic dimming mirror.

4. Strip 1/2" insulation from the radar detector power cord.

5. Locate the negative wire for the radar detector power cord. Twist the end of the wire to avoid fraying and insert it along side the wire going into terminal 3 of the 3 prong connector for the automatic dimming mirror.

6. Locate the positive wire for the radar detector power cord. Twist the end of the wire to avoid fraying and insert it along side the wire going into terminal 1 of the 3 prong connector for the automatic dimming mirror.

7. Place a narrow strip of duct tape to secure the radar detector power wire to the ceiling of the car. This helps prevent the wires from coming loose from the 3 prong connector.

If you are uncertain which terminal is 1 and which terminal is 3 use a volt meter or continuity checker - terminal 3 is ground and terminal 1 should read 12V with the ignition switch ON (II).

The above wiring procedure will allow the radar detector to power up when the car is running and will turn off when the car is off. One note of caution - the only protective fuse in the circuit is fuse #9 (7.5A).

If you have an expensive radar detector I would wire an inline fuse for the positive wire between the 3 prong connector and the radar detector.