Troubleshooting Replacement Turn Lights on Truck That Stop Working When Brakes Are Applied

Question:

Hello I am having trouble with my lights on my truck. I have a 5 wire harness that goes to my rear lights. I have replaced my factory lights and I am using stop/turn and running light that you would use on a trailer. I have installed a converter. Everything works until I hit the brake. When I hit the brake and I have a turn signal on the light that has the turn signal on goes out. I have tried hooking up the lights different and added ground wires to frame but have the same result. Is there a certain converter that I need?

asked by: B A

Helpful Expert Reply:

It is a good idea to check that you have a sufficient ground in your new wiring since the non-standard lights you're using may draw more power than the truck's original lights. Sometimes a weak ground will let some lights function while others do not. It is also possible that if they are incandescent type lights their total power demand is too much for your converter.

If additional ground wires to your truck frame are not correcting the issue I suggest you run a 10-gauge ground jumper wire like # 10-1-1 right up to the battery negative terminal. This will provide the best possible ground and allow maximum current flow to your lights.

expert reply by: Adam R