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Discussion Starter · #1 ·
Hoping some of you might have some ideas as I am left scratching my head...

To note - I am by no means an electrical engineer but pretty technology inclined, so if you wouldn't mind explaining it like I am 5 it would be appreciated.

My Rig: 2021 3121RL Legacy with a 2021 Chevy Silverado 3500DRW. My 5'er has the Hydrastar Brake Actuator and the HBA-CAM (which intermediary is supposed to fix things...).

My Problem: I am having intermittent brakes. For the most part I am always hearing the brakes - so I have connectivity (and the truck sees the brakes as connected), but when I actuate the manual brake controller it is very quiet sometimes and there is no breaking/stopping power with it. Sometimes everything works as expected, the HBA screams and will lock up the wheels.

When I am having the faint sound/no brakes, I have pulled the emergency brake cable and everything again acts as expected: The HBA screams, and calipers lock up the pads on the discs.

What I have done: I have chased the continuity of my brakes with my multimeter and 12v continuity tester, grounds, etc. everything is good there from truck and trailer side. I have re-terminated my connections, added new grounds, verified my my trailer batteries are fully charged (13.7v), removed from the cheap molded 7pin clip style and added a new automotive grade 7 blade connector, redid all of the connections from the 7way to the trailer wires, tried both of the connections on the truck (in the bed and on the bumper), ran an incandescent bulb on the brake line to increase resistance, tested my brake pin and ground pin on the 7way with a 12v incandescent tester with a manual brake controller activation - lights up bright. When doing that test, I hooked up my multimeter and saw 8v+ on a gain of 10 (this one is odd to me... but it might just be from the cheapie tester that I got from TrueValue)

Additionally I took it by a trailer shop which hooked up a battery powered trailer tester when I wasn't having brakes, and it controlled the trailer as expected, then we hooked the trailer back up to my truck and nothing besides a very faint sound from the HBA. As I just swung in they didn't have time to fully diagnose, but they did say they had a similar issue with another 2021 Chevy/GMC truck that they had in - but they said the couldn't fix it.

Anyone else experience anything like this, or have any ideas?

Has anyone bypassed the ITBC and installed an aftermarket brake controller on the new generation of HD's?

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