3121RL Legacy Disc Brakes Issue (Please help... running out of ideas)

[MiMontana]

Hello All,

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-16.

My Problem: I am having intermittent brakes. For the most part I am alway 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?

Thanks!

 

[Carl n Susan]

I believe the Chevy's need a conversion kit as the Integrated Brake Controller is somewhat incompatible with the disk brake actuator. Do a Search here as I remember this issue but don't know the specifics. It is likely someone will be along shortly with the answer. It may be something as simple as adding a old brake magnet to the electrical line.

 

[bobbecky]

Sounds like you need to get that truck into a Chevy dealer repair shop and have them fix the problem. From your description, it really sounds like a problem with the integrated brake controller in the truck, not the trailer.

 

[DTH-MOC]

Went through similar issues with my 2020 GMC. Dealer could not repair and was not able to get support from GM. I was not willing to put up with not knowing if the brakes would respond. I moved to Ram and have been very pleased. Brakes work very well with EOH system on the Montana. I had driven GM products my entire life before changing. Have no regrets. Really like my Ram 3500 and now feel like it does many things better.

 

[Tom N OH]

GM knows that they have an issue with trailer brake actuation & refuses to address it. The only 100% solution that anyone knows of is to change to another brand of truck. Not what anyone wants to hear, but it is what it is.

 

[DannyK-MOC]

DannyK

Had The same problem with my 2020 legacy and 2020 Chevy 3500. Resolved the problem with a brake actuator. The HYDRASTAR HBA-CAM 381-7073. Hydrastarusa.com. Hope that helps.

 

[MiMontana]

Had The same problem with my 2020 legacy and 2020 Chevy 3500. Resolved the problem with a brake actuator. The HYDRASTAR HBA-CAM 381-7073. Hydrastarusa.com. Hope that helps.

Thanks DannyK - Sorry in my description I put HBA-CAM-16 in actuality it is the HBA-CAM 381-7073. Which is supposed to work for me... but alas it is not. I have called Hydrastar and they were the ones that recommended adding the new ground.

Next steps is to use some of my connections within in GM to try to push them to fix this. Here's hoping I have some sway.

As for the others recommending getting a new truck, unfortunately that just isn't in the cards at this time. If all else fails I am going to try to figure out how to bypass the ITBC and install an aftermarket one...

c'est la vie.

 

[RMcNeal]

I have had mostly Ford trucks for year, but I was going to suggest using an aftermarket brake controller before purchasing a new truck. I think that would be much more cost effective unless you just want/need a new truck.

 

[Dexter1-MOC]

I’d suggest getting a stand alone brake controller. I bet a Prodigy p3 would fix your issues. It also probably wouldn’t hurt to try and have the brakes bled.

 

[jelders25]

Hello All,

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-16.

My Problem: I am having intermittent brakes. For the most part I am alway 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?

Thanks!

Hello from OKC, Dexter Axle's makes a specific brake adapter for your truck. I had to by one for my 2020, 3500HD., 2020 legacy.
I bought it from Performance Traler Braking.

 

[denhammkc@hotmail.com]

I have had mostly Ford trucks for year, but I was going to suggest using an aftermarket brake controller before purchasing a new truck. I think that would be much more cost effective unless you just want/need a new truck.

I second that

 

[ACKLM8]

No definitive solution or recommendation, however, I recall reading about trailer brake "communication" problems with Chevy or GM TV's on Facebook, so I only mention this to reinforce what appears to be the conclusion that this is a somewhat endemic issue with your truck make. Sounds like you have formed a good tactical plan. Good hunting!

 

[Mikelff]

I have noticed on my 2017 Silverado that sometimes the computer doesn’t recognize the trailer. I’ll shut off the truck and re start it then everything works as it should. After reading this thread I’m wondering how far back their trailer actuator problems go. Once it shows it’s connected to the trailer it works fine. Doesn’t happen often but on the rare occasion.

 

[bcrvman]

Hello All,

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-16.

My Problem: I am having intermittent brakes. For the most part I am alway 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?

Thanks!

That might be connected to the new trucks that do NOT put 12V back to the 7pin. IIRC there is a kit to fix the truck, but the kit also isn't 12V. Try searching the forum, this is not a new problem but my memory is poor.

 

[johnregrus]

I have a 2021 GMC Denali SRW Duramax and have two trailers both with the same disc brake setup you have. Both trailers disc brakes work flawlessly with the factory brake controller.

 

[beeje]

My 18 Chevy operates perfectly with my disc brakes

 

[MiMontana]

I have a 2021 GMC Denali SRW Duramax and have two trailers both with the same disc brake setup you have. Both trailers disc brakes work flawlessly with the factory brake controller.

Hi John - interesting, that gives me hope!

I just got home from my trip and will be dropping both off at their respective dealers. Hopefully either the truck or trailer dealers will be able to find my gremlin in the system.

Appreciate the insight!

 

[Hit The Road]

My 18 Chevy operates perfectly with my disc brakes

Same with our 2019 3500HD Duramax

 

[Banddkerr]

They say its fixed the issue now

I have a 2021 Chevy 3500HD and a 2016 Montana Legacy(no issue with breaks). I was looking at a new 2021/2022 Montana with Legacy package and saw the posts about incompatibility between my electric break and the disc breaks on Legacy package. I reached out the Team Montana and this is the reply I got today.

“The brakes on legacy package was an issue a year and half ago. Keystone has resolved the issue by installing a brake cam and I have had zero issues since.

Jarred Campoli, Team Montana”

Is he right?

 

[beeje]

Our fifth wheel has cam unit from cargo. From my understanding it basically allows the truck to recognize the electric over hydraulic brakes that are in the camper
I believe this is the part number without looking at it.
HBA-CAM. 381-7073