Tekonsha TK90160 Primus Brake Controller isn't Reading Trailer

Question:

Very first day I installed Primus IQ it worked great. Was able to calibrate it. Then the third time starting my tow car that day, it says n.c. been like that for a week. Even tried new battery because trailer had older one. Ive seen things to troubleshoot, but is there something obvious Im missing if it was perfect when installing it and driving for an hour? I used OEM harness to attach. No splicing. Thanks. Trailer is 2017 with minimal use so I dont think the trailer is the issue.

asked by: Zac

Helpful Expert Reply:

The NC error code means that the brake controller isn't 'reading' the trailer. This typically happens with a dirty/corroded/damaged trailer connector on the vehicle or on the trailer. Examine the pins/sockets on the connectors. Clean/repair/replace as needed. If the pins or sockets show white or green corrosion, you can try cleaning it off with sandpaper or a small file, but if the corrosion is severe, there's a chance that the corrosion has spread to the interior of the connector where the wires attach to the terminals and is preventing the brake signal from reaching the trailer brake magnets.

Worn brake magnets is a second possibility. If the above doesn't check out, pull the brake drums and examine the face of the magnets that ride against the inside armature surface of the brake drums. If the magnet is worn away to the point where you can see the interior copper wiring, the magnets need replacement.

Finally, check the brake output circuit on the trailer which is usually a blue wire. Trace that circuit back to the brake magnets, making sure there aren't any broken wires or loose connections.

I've linked you to our trailer brake controller troubleshooting article, which contains other helpful troubleshooting advice.

expert reply by: Mike L