im trying to locate the reverse wire that is in the column. im trying to find the wire color that actually signals the rear lights from the column shifter. Ive looked at all the exploded views on gmupfitters but havent been able to figure it out. i found the back up beeper wire to be light green underneath the cab but i tested all the light green wires from the column down and cant locate it. Does any one know the color of the reverse wire that comes from the column.

thanks in advance.

It looks like the power for the backup lights are activated by a pressure switch in the transmission instead of the shifter position. The wire from the pressure switch (PS4) to the TCM is Lt Grn/Blk. The wire from the TCM to the reverse relay is Gray. The power to the reverse relay is Pink and the power out of the relay to the lights and beeper is Lt Green.

This can be seen on page 212 of the upfitters guide (H63027a_005_02).

Hope this helps.

Like he said, Light Green. And the best place to pick it up is in the harness bundle behind the right removable fender well, or the factory junction panel, mid-frame, pass side.

The way they activate the back up lights tripped me up a few weeks ago. I was replacing the ugly "dump truck style" brake lights with LED's, even splurged on LED backup lights. I set the brake dropped the trans in reverse and turned the key to on, only to find no reverse lights. But thanks to this site a quick search for back up lights took me to a download of the upfitters wiring, there I found it, a strange way of getting the backup lights on.