Troubleshooting Factory Brake Controller in 2015 GMC Sierra 2500HD


Trailer is a 2012 Legend 29foot enclosed with new brakes backing plates, drums, etc. My truck is a 2015 GMC 2500hd with integrated brake controller Test truck is a 2006 chevy with an aftermarket brake controller When hooked to test truck brakes and lights work fine When hooked to my truck there are no brakes but lights seem fine Have had truck to dealer and they say there is nothing wrong with it Where should I go now?


Expert Reply:

Some factory trailer brake controllers are not compatible with trailers that use an electric-over-hydraulic actuator such as # HBA-10. Aftermarket controllers like the excellent Tekonsha Prodigy P3 # 90195 include a setting to allow for proper operation with this type of set-up, or with standard electric drum brakes. In your 2015 Sierra 2500 the P3 can be installed simply, using the custom wiring adapter # 3016 that plugs in under the dash.

If you do not have an EOH actuator, but instead have standard electric drum brakes, then you'll want to do some testing on your Sierra to determine if the brake signal is reaching its 7-way trailer connector. The brake signal from your integrated controller should appear on the contact at the 5-o-clock position as you view the socket. Please see the linked photo. You will need a circuit tester like # 40376 to test the circuit.

Apply the grounded tester to the brake circuit contact at the 5-o-clock position while a helper presses the brake controller manual override (with the controller set to maximum output). You should detect the controller's output signal on the contact. If not, then you will need to move upstream of the trailer socket to continue testing the wiring that feeds the connector.

You can refer to the linked article for more troubleshooting guidance.

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expert reply by:
Adam R

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