cancel
Showing results forย 
Search instead forย 
Did you mean:ย 

GM Duramax - NO Trailer Brakes

pcm1959
Explorer
Explorer
I have a 2013 HD with the factory integrated trailer brake controller. Today when I plugged in the fiver, NO brakes.
The DIC shows nothing but the the gain set point. I can adjust the gain up and down. No messages such as "trailer connected or trailer disconnect" nor any chimes.
There has been an occasion when I plug-in in the umbilical cord that I have had to jiggle it or unplug it and re-plug it to get a connection but that is rare. Once its connected I have never had an issue. In addition I do have the in-bed plug as well as the one near the bumper but neither would work today. I looked underneath but all the wiring looks fine.
All of the trailer lights work - turn signals and brake lights.
I connected a tester to the vehicle end plug to test the function of each blade. When I tested the brake blade, there was a very, very slight pulsing of the test meter needle even without pushing the brake pedal OR the manual brake control on the ITBC. Pressing the brake pedal or manual control made no change.
I do have e/h Dexter disc brakes on the fiver with the HBA-Cam adapter for the disc brakes. I checked all the wiring connections and they all looked fine.
I pulled the trailer on Friday with no issue. The trailer and truck were parked until today and now in 3 days, now no brakes.
Am I correct in that this issue is on the truck end since I am not getting any output with the test meter when testing the "brake Blade" on the vehicle end?
I checked 3 fuses......number 19 ITBC, 58 Stud 2, and 63 Stud 1. Number 19 is ok. The other 2 are fuses I'm not familiar with, however, compared to the others like it there was no difference in their appearance.
I plugged-in the RV again and no change. No messages at all on the DIC. Plugging and un-plugging the umbilical cord creates no messages or chimes.
Thanks, Phil
2018 GMC Sierra 3500 DRW 4x4 Duramax/Allison
2014 Lifestyle LS36FW
St Augustine, FL
30 REPLIES 30

pcm1959
Explorer
Explorer
Roger10378 wrote:
You do realize that the IBC does not apply brake power when you are not moving. I guess that is so that you don't burn thing up if stuck in traffic.


No, I did not know that and sure wish I had seen your post advising of such.....sure would have saved me some time. Thank you.
2018 GMC Sierra 3500 DRW 4x4 Duramax/Allison
2014 Lifestyle LS36FW
St Augustine, FL

pcm1959
Explorer
Explorer
UPDATE!!! BRAKES WORK NOW!

All along, the problem was the HBA-CAM module that is required for some truck models with factory ITBC to work with EHB trailer brakes.

Others had suggested that and I did replace the 4 wire Carlisle model with the Titan 2 wire model. I noticed when shopping for a new module that the Carlisle model had gone to 2 wires.

At any rate, yesterday after replacing the module everything worked except when pushing the brake pedal. I did not know that the trailer brakes would not activate when pushing the brake pedal without the truck moving. If stationary, the brakes activate the if the gain is turned up all the way or with a stronger force on the brake pedal. Again, I think this is a design to avoid burning out the pump (or electric brake magnets for those without disc) while in traffic.

So for those with disc brakes that have to use an adapter, it may be worth getting a back-up module in the event it goes out on the road like mine did.

Thanks to those who offered help in this situation. Phil
2018 GMC Sierra 3500 DRW 4x4 Duramax/Allison
2014 Lifestyle LS36FW
St Augustine, FL

Charlie_D_
Explorer
Explorer
Check for a bad fuse on the left side of the dash. Open the door and there is a panel on the side of the dash. Had a blown fuse at that location one time.
Enjoying Your Freedom?
Thank A Veteran
Native Texan
2013 Prime Time Crusader 330MKS
2018 Chevy 2500 D/A Z71 4x4 Offroad
2006 Holiday Rambler Savoy 33SKT-40,000 trouble free miles-retired
2006 Chevy 2500 D/A-retired
2013 Chevy 2500 D/A-retired

Roger10378
Explorer II
Explorer II
You do realize that the IBC does not apply brake power when you are not moving. I guess that is so that you don't burn thing up if stuck in traffic.
2005 Cardinal 30TS
2007 Chevy 2500HD D/A

Bessie-Hunter
Explorer
Explorer
Did you get the 2 wire HBA-CAM or the 4 wire one?

pcm1959
Explorer
Explorer
UPDATE:
On advice of a few others with this situation, I have replaced the HBA-CAM module/adapter. The trailer brakes now work when pulling the break-away switch and when using the manual brake toggle on the ITBC.
I get the messages on the dash DIC such as trailer connected or check trailer wiring when I unplug it. However, I am not getting any activation of the trailer brakes when pressing the truck brake pedal. The graph on the DIC increases but no brakes.
Any suggestion for this one? Thanks, Phil
2018 GMC Sierra 3500 DRW 4x4 Duramax/Allison
2014 Lifestyle LS36FW
St Augustine, FL

Bessie-Hunter
Explorer
Explorer
Don't know how much the new HBA-CAM will cost you, but I installed two brake magnets at the Dexter pump so my Siverado would "see" the trailer.
GM's brake control needs to see a resistance and an inductance in the brake circuit before it lets the controller work.

pcm1959
Explorer
Explorer
tomman58 wrote:
When my GMC does that I clean up the contacts on both the plug and truck put some contact stuff on them and plug it in.


I wish that was the issue.
2018 GMC Sierra 3500 DRW 4x4 Duramax/Allison
2014 Lifestyle LS36FW
St Augustine, FL

tomman58
Explorer
Explorer
When my GMC does that I clean up the contacts on both the plug and truck put some contact stuff on them and plug it in.
2015 GMC D/A, CC 4x4/ Z71 ,3.73,IBC SLT+
2018 Jayco 338RETS
2 Trek bikes
Honda EU2000i
It must be time to go, the suns out and I've got a full tank of diesel!
We have a granite fireplace hearth! Love to be a little different.

pcm1959
Explorer
Explorer
UPDATE: I plugged the truck into another RV and everything functions properly. I'm going to order a new HBA Cam module and see if that fixes it as others have suggested. I can't imagine what else it could be since the brakes activate when pulling the break-a-way plunger as well as all the lights including back-up work. I'll update once I receive the new part and install. Thanks.
2018 GMC Sierra 3500 DRW 4x4 Duramax/Allison
2014 Lifestyle LS36FW
St Augustine, FL

pcm1959
Explorer
Explorer
I have changed out the trailer end plug today. No difference. It is a much better tighter fitting plug, however. That's how I can rationalize that waste of time. LOL
I'm hoping to be able to plug my truck in to a neighbors trailer sometime soon to see if I get the appropriate messages on the DIC.
If that's aOK, then I am going to replace the HBA Cam. Three people have mentioned they go bad! Go figure.....an encased magnet going bad! The one I currently have (Carlise 381-7063) must me an older model as it has 4 wires coming out of it and the newer one with the same model number only has 2 wires as does the one from BrakeRite. I called Dexter (who has purchased BrakeRite) and was told that the BrakeRite adapter is compatible with the Dexter pump.
2018 GMC Sierra 3500 DRW 4x4 Duramax/Allison
2014 Lifestyle LS36FW
St Augustine, FL

pcm1959
Explorer
Explorer
Thanks to everyone for all the replies. Once Irma has passed (and if the fiver is not destroyed) I will update my findings. Safe travel!
2018 GMC Sierra 3500 DRW 4x4 Duramax/Allison
2014 Lifestyle LS36FW
St Augustine, FL

Michelle_S
Explorer II
Explorer II
Had the same exact problem a few years ago. Pulled into a CG with everything working, few days later go to leave and NO Brakes. Don't ask how or why, but the CAM module died. Replace and all good, so now I carry a spare just in case.
2018 Chevy 3500HD High Country Crew Cab DRW, D/A, 2016 Redwood 39MB, Dual AC, Fireplace, Sleep #Bed, Auto Sat Dish, Stack Washer/Dryer, Auto Level Sys, Disk Brakes, Onan Gen, 17.5" "H" tires, MORryde Pin & IS, Comfort Ride, Dual Awnings, Full Body Paint

Bessie-Hunter
Explorer
Explorer
Replace the HB-CAM with an electric brake magnet.