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Electric Over Hydraulic Brakes Don't Work w/Brake Pedal on Newer GM Trucks w/OEM Brake Controller


My company has a Walton two axle heavy duty trailer with electronic over hydraulic brakes. Most of our trucks are newer Chevys or GMCs. After electrical testing I found the actuater on the trailer to be faulty. I replaced the actuater. The truck can sense the trailer, but I can only engage the trailer brakes using the manual slide on the brake controller in the cab. The brake pedal does not engage the trailer brakes. All the wiring is as it should be. Ive read that some trucks had problems with E/H brakes and thier factory installed tow packages, but that had to do with the truck not sensing the trailer. If you have any ideas about why the trailer brakes only engage with the manual lever and not the brake pedal I would very much like to hear them.


Expert Reply:

Like you said, many factory integrated brake controllers will not work well with electric over hydraulic trailer braking systems. Some of the newer versions of these controllers now have an electric over hydraulic mode. Check to see if any of your trucks have this mode and, if they do, if the braking starts working with the pedal.

Otherwise there are a couple of solutions to solve this issue. First, there may be an adapter that will allow the factory controllers to work but it depends on the actuator being used. For example, there isn't an adapter for the Dexter actuators such as # K71-651. But there is one for the Hydrastar # HBA16; adapter # HBA-CAM.

The other option is to switch all of the trucks to aftermarket brake controllers that are compatible with electric over hydraulic braking systems such as the P2 # 90885 or the P3 # 90195. I have included a link to a help article on installing an aftermarket controller on a 2007 to 2013 Chevy or GMC truck that has the factory integrated controller that should also help.

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