Troubleshooting Short-Circuit Error Code from Tekonsha Primus IQ Trailer Brake Controller TK90160

Question:

Do my trailer brakes work during this indicator?

asked by: Vic

Expert Reply:

The error code SH appearing on your Tekonsha Primus IQ Trailer Brake Controller # TK90160 tells us that the unit is sensing a short circuit on the blue output wire that powers the trailer brakes. This message could occur for any of several reasons. While you see this message the controller is unable to send power to the brakes.

The most common causes for this error are corrosion in either the vehicle socket or the trailer plug or damage to the blue brake circuit wire on either the vehicle or trailer side. Inspect the socket and plug for signs of even slight greenish or whitish discoloration, trapped moisture or dirt. Clean as needed. If this does not resolve the issue then check the blue wire from the trailer plug all the way back to the brakes looking for signs of worn or cracked insulation, or the wire rubbing against the trailer frame, especially in places where it has to make sharp bends. Repair or replace any such damaged wiring.

You can also directly test the trailer brakes, without connecting it to the tow vehicle, by applying 12V power from the vehicle (or another) battery directly to the brake circuit on the trailer plug. I linked a photo for you that shows which pins to connect for testing.

expert reply by: Adam R