Troubleshooting SH Error Code on Tekonsha TK90160 Primus Brake Controller  

Question:

Helpful Expert Reply:

I've confirmed with my buddy at Tekonsha that what you are experiencing is indeed a short circuit somewhere in the brake output circuit. The first thing you'll want to do is isolate the problem to find out if the short is in the brake controller itself, the truck wiring or the trailer wiring.

If the SH error code doesn't go away when the trailer is unplugged, the short is either in the truck wiring or the controller itself. If it DOES go away, the problem is within the wiring on the trailer.

To determine whether the problem is in the truck wiring or the controller, cut the blue wire exiting the rear of the controller. Leave enough room so you can splice the wire back together. If cutting the wire does not eliminate the error code, the controller has an internal short circuit and should be replaced.

If the error code goes away with the wire cut, first closely examine the trailer connector at the rear bumper of the vehicle. If it's damaged or corroded clean or replace the connector. If the connector's okay, the short likely lies in the output circuit between the trailer connector and the blue wire on the brake controller. You can use a length of wire like part # 10-1-1 to run a new output circuit. Connect the wire onto the blue wire you cut behind the controller and run the wire through the firewall, through the engine compartment and under the vehicle. Be sure to avoid anything hot or moving like suspension or steering components. On the back of the trailer connector, peel back the wire loom and look for a blue wire exiting the rear of the trailer connector. Cut this wire several inches forward of the trailer connector and connect to the wire you ran from the front.

If you've determined that the short is in the trailer wiring, begin with the connector on the trailer. Check for damage or corrosion. Trace the brake output circuit (usually a blue wire) from the trailer connector back to the brake assemblies. Make sure the wire is in good condition, and isn't pinched. Make sure the wire insulation isn't cracked or worn, allowing the wire to short out on the trailer frame. Make sure all connections are tight, including the ground for each brake magnet. Worn brake magnets might also be causing the problem you're experiencing. Pull each hub off and examine the brake magnet. If you see the face of the magnet is worn to the point where the copper wiring in its interior is visible, the magnet is shot and should be replaced.

Finding the problem might take some time, but if you're logical about it and follow the steps outlined above, you should be successful. I've also linked you to our brake controller installation troubleshooting page.

expert reply by: Mike L

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