have a 2003 Chev d/a 4x4 cc. installed a Tekonsha Prodigy brake controller for towing. the install just snapped into an existing clip. problem is the brake now causes the left blinker to work. the left blinker causes the brake lights to work and the right blinker works as it should when connected to a trailer. the truck works fine on all modes, just the trailer lights work incorrectly. any thoughts?

I believe there is a different wiring harness for the '03-'04 trucks. Tekonsha has them on their website.


If you e-mail them, they will send you the correct wiring diagram for your model truck.











Kevinhttp://www.dieselplace.com/forum/smileys/Big Smile.gif





Oops! didn't realize this was the Tech forum...Sorry!http://www.dieselplace.com/forum/smileys/Embarrased.gifEdited by: Fireman

Info I have found:
If your are using a standard 7 pin trailer plug you can test as follows.
With the trailer disconnected make the following checks on the trailer plug on your truck.
With an annalog voltmeter, I say annalog because a digital has too slow a responce time, connect one side of the meter to a good truck ground.
With an assistant forward and looking into the trailer plug you should see the following functions at these locations. Battery at the pin at 1 oclock, right directional at the pin at 3 oclock, brakes at the pin at 4 oclock, ground at the pin at 7 oclock, left directional at the pin at 9 oclock, and parking lights at the pin at 11 oclock. The center pin is a spare and may also be wired as a ground,
If this all checks out right your truck wireing is set up in a standard way. Go to the plug on the trailer. Test for voltage between a trailer ground and the pin at the 1 oclock position. This should be your trailer battery. Now check voltage between 1 oclock and 7 oclock. 7 oclock should be trailer ground. If you have voltage on the trailer use a piece of number 14 or smaller wire or use a wire with a 20 amp fuse in it, and insert one end into the position at 1 oclock. Touch the wire to position at 9 oclock, the left brake light should come on. Touch the positon at 3 and the right brake should come on. Touch the position at 11 and the parking lights should come on. Last jack up one side of the trailer and while someone spins a wheel touch the position at 7 oclock, this shold be trailer brakes.

The cover at the bumper recept. is stamped to show what each of the seven pins represents.Your recept. in the box should be wired the same.Also the wiring harness from the brake controller to the truck differs from the 2002 year to the 2003 year.The end which plugs into the truck has each wire terminal stamped as a,b,c,d,e,or f.The lite blue wire which is for stop signal from truck stop switch to brake controller is on terminal A for 2002 and on terminal D for 2003,probably 2004 also.If you have the 2002 harness just remove the brown wire which is for contoller illumination from terminal D and put the lite blue wire from terminal A in its place.The brown wire is not needed on the Prodigy.