Trouble Shooting a Primus Brake Controller on a 2003 Chevrolet 2500 HD

Question:

I hooked up my trailer and truck the first time this spring. The truck is a 2003 2500 HD chevy new to me with a Primus brake controller with proper pigtail to plug into a chevy truck. I removed the controller that was in the truck and put my better Primus in. When I first plugged in the trailer plug the display on the controller showed a number like the brake pedal was pressed but it wasnt. I unplugged and plugged back in and then it just had the two dots like it should but when you push the brake pedal nothing came on, but the manual override would activate the brakes. I tested the voltage to truck plug and it had 10 volts to the brake spade. Where do I start? The controller manual said there could be a charging system error or inadequate connection to tow vehicle battery. This trailer has a break away system on it and that battery only had 3 volts, could this be my problem? I have it hooked to the truck now charging. TIA

asked by: Christopher

Expert Reply:

Often times if break-away kits are not wired properly, they will cause problems with a brake controller. The first thing to do would be to make sure there is not a problem on the vehicle.

Disconnect the trailer and turn on the truck. You should see one dot on the display, in the center, indicating that the brake control has power and is active, but there is no trailer connected. When you apply the manual lever with no trailer connected the display should read n.c.. If all this works right, chances are there is something wrong with the trailer or break-away. I would also use a circuit tester, part # PTW2993, or a 7-Way tester, part # C73NR, to check the 7-Way at the truck. The Primus will actually see it as a trailer.

Completely disconnect the break-away kit from the trailer and put the wiring back together so the trailer is wired properly. Connect the trailer and re-test. With a trailer connected and truck running, you should have dot c on the Primus display indicating that the brake controller has power and that a trailer is connected. When you apply the manual lever, you should see a number on the display.

If these conditions do not happen, then there is something wrong with the trailer and you need to check the wiring and get the trailer working right before you add the break-away kit back in. If everything does work fine, than the break-away kit was the problem and you will just need to add it back to the system properly following the break-away instructions.

If you determine that the break-away kit is the problem, you can write back and let me know what kit you have and I can try to find instructions for it and help you re-install it.

expert reply by: Patrick B