Troubleshooting Flashing C on Display of Tekonsha Primus IQ Trailer Brake Controller TK90160

Published 12/01/2016

Question:

I bought this brake controller and had it installed by a professional that sold it to me its been used one time. I get in my truck to go to work this morning and it is constantly flashing a C every 3 seconds. It is not connected to my camper.

asked by: Nicholas B

Expert Reply:

If the Tekonsha Primus IQ Trailer Brake Controller # TK90160 displays the flashing letter C even when no trailer is connected the cause is likely to be an issue with the 12V power connection to the controller. The flashing C indicates that the Primus is trying to reset itself after power interruption.

According to my contact at Tekonsha most often this issue is caused by a bad main power connection to the controller, which is carried on its BLACK wire. Make sure the input power wire is tightly connected at the battery and circuit breaker. Also check the WHITE ground wire for solid connection. Chances are that one of these two wires is not making a tight enough connection.

You can try removing the battery connectors from the battery and sanding them with fine grit sandpaper to remove any oxidation that might be interfering with the power delivery.

expert reply by: Adam R