Tekonsha Primus Brake Controller Showing SH Error Code When Trailer is not Connected

Updated 03/17/2024 | Published 08/16/2012

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Question:

code flashing on brake controler is s h the book says there is a short in wiring but it flashes with and with out trailer hooked up

asked by: Frank J

Expert Reply:

The SH error code indicates a short circuit in the brake controller output. Since it is occurring when the trailer is not connected, it would eliminate the trailer wiring as being the problem.

The trailer connector itself is the usual suspect in this case. Check the connector for damage or corrosion. If you can see any white or green corrosion on the pins of the connector, there is a good chance that the corrosion has spread to the interior of the connector, where the wiring connects to the terminals. If this corrosion becomes severe enough and builds up on the terminals, it can cause a short to an adjacent terminal.

If the connector checks out okay, locate the blue wire exiting the rear of the controller. Sever the wire several inches rearward of the controller (so there is plenty of available wire to reconnect it). If cutting the wire solves the problem, the short exists somewhere in the wiring between the connector and the brake controller. You can trace the wire if you care to, looking for loose connections or worn or cracked insulation, but this might be difficult depending on the vehicle. Your best bet might be to simply tap in a length of 10 gauge wire like # 10-1-1 and run it from the blue wire on the controller to the # 2 terminal on the connector. This would bypass the defective wire.

expert reply by: Mike L

Shaun H.

3/16/2024

Mike, I am having the same issue as Frank on my 1994 K1500. I installed the 7 pin harness pt#ETBC7 and the tekonsha p2 brake controller pt#90885 step by step from the etrailer video. I then had the same SH error code. I double checked all connections and the brand new 7 pin terminal all is well. I even ran a new blue wire from the 7 pin terminal to the blue wire on the brake controller with the same issue. Is it likely that the trailer brake controller is faulty right out of the box? Thanks, Shaun Hammond.

Mike L.

3/16/2024

@ShaunH It's possible, but unlikely. Take a look at the connector on your trailer. Make sure none of the sockets on the connector are corroded. Trace the blue brake output wire from the connector back to the brake magnets, making sure there aren't any loose connections. Pull one of your hubs and check out the face of the brake magnet that rides along the inside surface of the brake drum. if the magnet is worn to the point where you can see the copper wiring showing, then the magnets are worn and need replacing. I'll link you to a troubleshooting article that will help.

Helpful Links

faq-brake-control-troubleshooting.aspx

Shaun H.

3/17/2024

@MikeL Sir this is happening when the trailer is not connected. Since all the parts are new including all the wiring it seems like the brake controller itself is faulty. Is there any way to test this?

Mike L.

3/17/2024

@ShaunH Since the 7-way on the vehicle and its wiring are new, and you've ran a new output circuit, It would seem that the brake controller is at fault. One more test. Disconnect the blue wire where you connected to the brake controller. If the SH code doesn't disappear, then the controller is faulty and should be replaced, and you'll want to call our Customer Service folks at 800-298-8924 to arrange for a warranty replacement. If it does disappear, then there's some sort of wiring issue between the controller and the trailer connector on that output circuit.