[SOLVED] EOH trailer brakes?

Anyone had issues with EOH trailer brakes? My 2026 AT4 Ultimate towed my race trailer with electric brakes just fine 10 days ago, but I connect my boat trailer with Dexter (not Hydrastar) EOH brakes and it doesn't see the trailer brakes (although the trailer lights all work fine).

I swung by the small GMC dealer near the boat storage and they verified that the truck didn't see brakes with their test tool, then did a "Global Reset" (aka disconnected the battery for a few minutes) and then the brakes showed up on the test tool. But as soon as I plugged my boat trailer back in, same problem.

Anyone seen this before I go fight with my home dealer service dept ("we can't replicated it")?

A different year but my 2023 Suburban has always played well with my EOH trailer brakes. It is a Dexter set up. It might be worthwhile to give a shout to Dexter.

Padraig

sohanrd said:

6.2 or 5.3?

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strangeengine said:

Anyone had issues with EOH trailer brakes? My 2026 AT4 Ultimate towed my race trailer with electric brakes just fine 10 days ago, but I connect my boat trailer with Dexter (not Hydrastar) EOH brakes and it doesn't see the trailer brakes (although the trailer lights all work fine).

I swung by the small GMC dealer near the boat storage and they verified that the truck didn't see brakes with their test tool, then did a "Global Reset" (aka disconnected the battery for a few minutes) and then the brakes showed up on the test tool. But as soon as I plugged my boat trailer back in, same problem.

Anyone seen this before I go fight with my home dealer service dept ("we can't replicated it")?

Click to expand...

So, have you talked to dealer or Dexter? Please let us know

Padraig

I ultimately solved this with one of the EOH adapters available - it basically has a magnet so it tricks the brake controller into thinking there are electric brakes vs EOH. Works fine. I used the Deutsche Hydrapro adapter from etrailer.com but there are others from Dexter and Hydrastar as well.

The debug was a PITA because my Yukon also had a blown 30A trailer power fuse and the EOH pump needs that circuit hot. Took a few hours longer than it should have as a result. I also got to learn that the local GM dealer charges NINE DOLLARS for a 30A fuse.

Big thanks to GM for making this WAY more complicated than it needed to - my old Navigator had a setting for EOH brakes to avoid this whole issue.

Great that you got it working. It is strange that my EOH works fine with my 2023 Suburban and adapter is not needed. I knew about adapters being available but didn't think you would need one when my older vehicle didn't.

Padraig

Padraig said:

Great that you got it working. It is strange that my EOH works fine with my 2023 Suburban and adapter is not needed. I knew about adapters being available but didn't think you would need one when my older vehicle didn't.

Padraig

Click to expand...

I agree - kinda weird. I suspect it's a 25-26 issue.