Troubleshooting Brake Controller Not Powering Up on a 2003 GMC Sierra with Factory Tow Package

Question:

Please Help me.....In May I purchased a tekonsha prodigy brake contoller and a 3015-P wiring harness. I finally had time to install it the other day and I cannot get it to work. I have a 2003 GMC Seirra and I have a factory-wired 7 wire tow package. I installed the 3015-P wiring harness to the fuse box underneath the dash exactly how your website describes. The prodigy display is blank with/without the trailer hooked up to it no power to the unit?. The trailer signal lights/brake lights work normal. I have a multi meter. Did I get a defective unit?

asked by: Rich D

Expert Reply:

There are actually a few connections you will need to make under the hood to get the brake controller and tow package fully functional on your 2003 GMC Sierra. Under the hood, on the drivers side towards windshield, there is a bracket you will need to remove to gain access to the Accessory Fuse Block and lower fuse housing. Remove the top cover on the Accessory Fuse Block and the lower cover to the fuses. You will find a blue and red wire next to the fuse block. The blue wire has a plug on the end and the red wire has a ring terminal.

Attach the red wire to the nearest positive post. Then place a 20 or 30 amp fuse in the location nearest the positive post to power the brake controller (see brake controller instructions for which size to use). If the wires are already connected, check to make sure the correct size fuse is in the correct location to power the brake controller.

Next, clip the plug off the blue wire unless it is connected to a wire leading under the truck. If it just has a plug at the end, you will attach a length of jacketed wire, # 10-2-1, long enough to be routed under the truck to the 7-Way trailer connector. Attach the white wire in this cable to the blue wire. Next, check for 12 volt power at your trailer connector using your multimeter. The 12 volt pin is in the 1'oclock position if facing the plug. If you have power then you will route the white wire under the truck, along the frame rail, to the back of the 7-Way and attach it to the wire coming out of the 7 o'clock position.

If you do not have power, connect the black wire to the positive battery terminal via a 40 amp circuit breaker, # PK54540. Then, route both wires under the truck to the 7-Way. At the 7-Way, attach the white wire to the wire coming out of the 7 o'clock position. Attach the black wire to the wire coming from the 11 o'clock position.

I have included an FAQ article on installing a brake controller on a GMC Sierra that should help. There are also some pictures that should help you identify the specific areas I have mentioned above.

expert reply by: Michael H