Troubleshooting Brake Controller that Gets Hot with OL and SH Error Code

Updated 01/11/2016 | Published 01/10/2016

Question:

I dont have a manual for this brake controller and have really never worked with it. While towing a horse trailer I noticed it flashing oL which I have determined to mean overload. When I touched the controller it was so hot it almost burned my hand. But I dont know how or what to do to remedy the ol. Other problems that occurred right after I disconnected and then reconnected the controller, which may or may not be related, the left turn indicator does not work on the trailer and now I see an occasional sh code on the brake controller. I take this to mean there is a short. How best to approach the diagnoses of these problems?

asked by: Bill

Helpful Expert Reply:

A brake controller should not get so hot that it would almost burn your hand. The OL or Overload error code is displayed when the brake circuit is drawing too much current, possibly caused by a short on the brake wire or a poor ground connection at the brake magnets.

Since you are occasionally getting SH codes as well then it really sounds like you have a short on the brake output wire. Most likely on the trailer side of the wiring. Go over the brake output circuit looking for any cuts or exposed wire that could be causing the short and fix as needed. Shorts can also be caused by corrosion on the trailer connectors so check there as well.

I attached a help article on troubleshooting brake controller installs for you to check out as well.

expert reply by: Jameson C