Troubleshooting A Non-Functioning Tekonsha P3 Brake Controller

Question:

Tekonsha P3 brake controller has power to the back of the supplied wiring harness but when I plug it in there is no power to the head control unit. 12V between the black supplied from red with black tracer manufacturer and white supplied from white manufacturer. Which would mean that it isnt a supply fuse issue. Is my controller defective?

asked by: Ryan B

Expert Reply:

Hey Ryan,

Are you saying that the P3 # 90195 screen isn't even lighting up or that you're just not getting 12 volts out from the unit? The wire harness needs to be wired with black to the battery with a 30 amp in line circuit breaker # 38630, white to the frame for ground, blue to the brake controller output pin on your 7-way, and red to the cold side of the brake light switch. Since the brake light switch wire in your Silverado is too small to splice into I recommend installing a stop light switch # RM-751000 to simulate the brake switch signal.

If you're saying the unit is getting 12 volt power and still not turning on then it definitely sounds faulty to me and so I would reach out to Tekonsha for a warranty replacement.

expert reply by: Kevin C

Ryan

5/8/2024

Hey Kevin, I was getting 11.4V to the pig tail of the supplied wiring harness however when I plugged it into the back of the brake controller the screen would not turn on. On further investigation o found that the panel of the fuse box was not seeded fully causing it to get enough to show I had power but not enough to supply load to the device. Thanks for reaching out. It has worked since re seeding the panel of the fuse box.