Brake Warning Light Flashes on 2004 Dodge Ram with P2 Trailer Brake Controller Plugged In

Question:

After installing a P2 in my 04 Dodge Ram with 4 wheel drive, I noticed the brake warning light on the truck dash is flashing. I used the adapter wiring harness that plugs into the truck receptacle. Any idea what is causing this?

asked by: George B

Expert Reply:

I spoke with my contact at Tekonsha about the issue you are having with your 2004 Dodge Ram. The way the P2, # 90885, is designed, it can only receive a signal along the red wire and on the truck it sends that signal from the center high mount stop light circuit which is a dedicated brake light. What this means is that the P2 cannot interfere with the truck wiring.

Check the CHMSL circuit fuse (see owners manual) and the light itself to determine if either is out. This would also cause the controller not to work with the brake pedal.

First, check to see if the P2 is functioning correctly. If it is then it could just be a coincidence. If the brake light goes out when you disconnect the P2 this could mean that the # 3020-P harness is connected to the wrong plug under the dash. You need the plug like in the video I have linked.

expert reply by: Michael H