Troubleshooting Trailer Brakes That Stop Working When Trailer Is Hitched To Truck

Updated 04/12/2021 | Published 04/08/2021

Products Featured in This Question

Replacement Trailer Brake Magnet for 12" Brake Assemblies

(40)

$29.03

10 Gauge Wire - Blue Primary - Per Foot

(108)

$1.65

Deka Heat Shrink Butt Connector - 12-10 Gauge - Nylon Insulation - Yellow - Qty 5

(1148)

$8.08

Question:

Our electric brakes work when the trailer is plugged in to a truck, but not on the hitch. When we put the trailer on the hitch, they quit working. Thoughts?

asked by: Josh

Expert Reply:

Based on your description there is an issue with the wiring running from the 7-way connector to the trailer brakes on your trailer, but I will say this is a very odd issue.

I recommend tracing the trailer brake output wire from your trailers 7-way looking for any damage or any places it might be getting pinched when the trailer is hitched to your ball mount. Replace any damage sections with # 10-1-1 and heat shrink butt connectors # DW05745-5.

It is likely that the wires are getting pinched somewhere when hitched, or there is damage to the wire that is shorting out when hitched.

I included a link to a helpful article on wiring for you to take a look at.

expert reply by: Samuel C