Troubleshooting Factory Brake Controller Saying Check Trailer Wiring on a 2024 Chevy Silverado 5500

Updated 10/06/2025 | Published 10/03/2025

Question:

I purchased two new 5500s cab and chassis. Put work beds on both and hitched them to two new Big Tex 25GN-30D5A-MRBK trailers with electric brakes. Immediately have issues with check trailer wiring. Intermittent brake control loss. both trucks have had service update for the brake controllers and all service bulletins have been cleared. The 7 pin connectors on the beds have been inspected and the trailers have been inspected. In fact, the trailers work fine behind two older F350s. And, when i hook the trucks to another gooseneck trailer in our fleet i have the check trailer wiring issue.

asked by: Jim D

Expert Reply:

Hey Jim. Did the Trailer Brake Control Module get replaced when you had the new trucks serviced? What your describing is word for word the issues the factory brake controllers have been having on the 2019-2025 Chevy Silverado 5500s.

The trailer battery voltage exceeds the truck's main battery voltage, a voltage feedback occurs. This creates a false short to the ground, which deactivates the trailer brakes and causes a "check trailer wiring" message on the instrument cluster.

expert reply by: Jerred H

Jim D.

10/6/2025

Jerred, yes. the trailer brake control module did get replaced in the both trucks. This did not solve the problem. jim

Jerred H.

10/6/2025

@JimD That's interesting. You said you were running electric brakes on the Big Tex trailers. Are those electrically controlled hydraulic brakes or standard electric brake assemblies? That's the only issue I can see that could cause the trailer not to work with your trucks. Those need an adapter depending on what actuating system the trailers use.

Jim D.

10/6/2025

@JerredH, the brakes are electric only. No hydraulics. jim

Jerred H.

10/6/2025

@JimD Ok, yeah I would take it back to the dealer then. There's something still wrong with the factory brake controllers. I do not have any way of troubleshooting them.