Internal Brake Controller again

[Steve & Linda]

Well here is my somewhat similar situation. I've been pulling our Redwood with a 2014 Silverado 3500 dually with no issues. Bought a new 2017 this year and after loading up the Rv for a trip, the DIC told me to check trailer wiring. No brakes. I pulled the e-stop cable and the actuator worked. Had someone pump brakes and the actuator is silent. So I am assuming that the problem with mine is in the truck. I have a 7-way in bed mounted by hitch people and the bumper 7-way from GM, no difference. I do not have the puck system. I'm not mechanically minded, so where do I go from here?

[MuddFlap]

Steve & Linda, First a couple of assumptions/clarifications: I assume the first RV had standard electric drum brakes and the new RV has hydraulic disc brakes? If so, here is what I’ve learned in the last 72 hours or so: according to Hydrastar compatibility chart https://www.hydrastarusa.com/pdfs/Compatibility%20Chart%20Revised.pdfGMC/Chevy trucks need the HBA-CAM. It’s pretty simple to install, requiring two wires to be spliced into existing actuator wiring: https://www.hydrastarusa.com/pdfs/hbacamInstructionSheet1.pdf

The puck system has no bearing in whether your truck is compatible or not.

Also check the wiring on the new RV. (See HBA-CAM installation sheet) Some people have had incorrect wiring issues. Mine looks to be wired correctly although Redwood used different color coded wires from the pinbox connector to the brake actuator. I had to use an ohm meter to trace the wires from the pinbox connector to the actuator.

When I spoke to Tye at Hydrastar 812.655.4544 (Eastern Time) he said that if you press the brake pedal and the pump doesn’t immediately activate then there is a “communication” issue between the truck and RV. I’d suggest that you contact Tye to get professional advice.I’d wager that an HBA-CAM (about $100 part) will resolve your issue. Any reputable trailer shop should be able to perform the installation.

[MuddFlap]

So I blead the brakes today... wow! First checked the fluid level: less than a quarter inch of fluid in the reservoir! OMG! There couldn't have been more than an ounce of fluid in there. There's four large two piston calipers, that's gotta be a few ounces at least to activate them. Every time I hit the brakes it was pumping more air into the system. Ok next I blead the actuator, small amount of air and clean brake fluid. Next, the furthest caliper. There's two bleed ports on each one. Each caliper had green contaminated fluid and significant amount of air. I used a quart of fluid and still didn't get clean fluid at the calipers. So at least there's no air in the lines. Big improvement on RV brakes now.

[Steve & Linda]

MuddFlap,
I'm sorry but I didn't give enough information. Our 2015 Redwood 38GK came with factory disc brakes. We pulled it for 3 years with the 2014 Silverado with no issues. What changed was the tow vehicle, this year we have the same Redwood but purchased a 2017 Silverado. And now the brakes on the trailer are not working. As said, the trailer actuator made noises when I was hooked up and pulled the e-stop cable, yet it is silent when pumping the brakes. The new truck also is telling me to check trailer wiring.
Sorry I didn't provide more information the first time. Does this change anything?
Thanks,
Steve

[boatguy]

Hi. I have had that happen. I took it to the dealer, they said they found nothing but changed out the plug anyway and said the trailer was bad. Then just this week when trying to diagnose my own trailer actuator I pulled the pin on the emergency while it was plugged into the truck. The truck didn't like it, I figure it had to do with power from the trailer battery and the truck both supplying power. It kicked a Relay and I got the dreaded message on the dash. Checked and the truck was putting out nothing. So I searched a few gmc forums and found out that 3 quick ignition cycles would reset it. I was doubtful but I did it and it corrected the message. The moral of the story for me was don't pull the pin with the plug attached.

If that doesn't work, just hit the local GMC dealer. If it's a 17 they have load testers for the trailer plug and they will fix you right up. Then we can get back to the problem on the trailer.

Hope that helps.

[MuddFlap]

Steve, that was MY mistake! I thought you got a new Redwood, now I see you got a new truck. So the RV was working fine with the previous truck but not the new one? Looks like boatguy had the same problem with a successful resolution. My knowledge about how the TV actuates the brakes is (currently) limited to checking the voltage at the 7 way plug. If boatguy's advice doesn't fix it then I'd suggest the dealer take a look.

[xtasee]

If you look back at my posts, my 2010 GM worked and the 2017 did not. Redwood thought they could hook the blue wire (controller) with the yellow (break-away). For some reason I can not explain, the 2010 with the CAM in the system did not have a problem. That said, the 2017 GM is now compatible with both brake systems whether you have the CAM installed or not. Drum electric or disc electric over hydraulic. However the break-away (yellow on the Hydrastar) and the controller (blue) must be two separate systems. To make matters worse, the white wire is for ground and Redwood had a white wire from the pin box that needed to be hooked to the yellow.... The fourth wire on the Hydrastar is black and that goes to the positive battery cable. Mine is connected in the pinbox.

If you check the voltage at the plug from the controller (blue) you will only get a constant +/- 1v. That is the truck sending test voltage down that wire. You will never get higher voltage through that wire to the pump until you are moving at 5 mph or better. Testing the plug will probably just frustrate you (as it did me) because the voltage will not go higher even if you operate the manual override on the controller. That is the way the system is designed and the truck is working properly. You need to see the message "Trailer Connected" before you will get brakes. Then when you operate the manual sliding switch, the brakes will work.

I doubt you have a truck problem. Follow every wire from the pin box. Once I corrected the wiring on the trailer, all was good on the 2017.

Hope that helps

[Steve & Linda]

I re-read this thread and realized that I do NOT get the "trailer connected" or the gain readout in the DIC, just "check trailer wiring". Unfortunately, I won't be able to get to it until after the 4th. Hopefully I'll have a resolution update to share.

[boatguy]

My brake problems have been resolved. As I mentioned in previous posts, my brakes on my brand new 2018 390MB locked up no matter what the gain was as soon as I stepped on the brake at all. We did all kinds of tests and had great help from Ron (aka Titan Guy) and Taylor Scott from Hydrastar. I can confirm that my 2017 3500 DRW Denali does not require the HBA Cam module. However, having it wired in does not affect it's use so we left it in place. Contrary to another post, the blue wire on the wiring harness will produce various voltage according to gain and braking even if you are in park. You do not need to go at any speed. The wiring from Redwood to the pin box was correct. Wiring on my truck was correct. The telling fact was that there was voltage on the yellow line from the actuator any time the brake was applied. That yellow line is the breakaway hot wire. Taylor from Hydrastar confirmed that was not how the actuator should act. They sent another one UPS with the return packing for an exchange and it arrived in 48 hours. The exchange took an hour and we had to bleed the brakes. While I have no doubt that my dealer would have done the job, I was not excited about driving to them with the state of the brakes.

So for anyone who was following, thanks and I can tell you it makes for a much less stressful drive.

[xtasee]

Originally Posted by boatguy

Contrary to another post, the blue wire on the wiring harness will produce various voltage according to gain and braking even if you are in park. You do not need to go at any speed.

You must have had the trailer connected.

[boatguy]

I'm going to assume your right Larry. I have never tried taking voltages of the plug without having a trailer connected. I use a pigtail plug that I made up specifically for testing lights, brakes etc. it relies on the trailer being connected to check grounds as well. Winter snowmobile trailers here are always having grounding issues so I always have them hooked up. I stand corrected

John

[xtasee]

John,

Believe me no offense intended. I was just checking at the plug as someone else described they were going to do. When I could not get anything more, from operating the controller manually, than +/- 1V on the blue, I believed it was the truck with the problem. I took it to the dealership and they also got the same result and looked up several technical bulletins.

They were the ones who told me that the truck had to see a trailer connected before it would send voltage down the blue from the controller. YMMV,

Anyway I am super glad we both got to the bottom of it! It appears that neither one of us had an actual issue with the truck.

[boatguy]

Not offended at all! This was one of the most helpful threads I have used this month. I would hate to think how long I would have driven with bad brakes.

[mhs4771]

With GM's it's not so much seeing the trailer connected as it is the Low Resistance of the Magnet Coils. That's where the CAM comes in, it supplies the proper low resistance to fake out GM's (prior to 2017) into thinking it's connected to standard electric drum brakes.
I actually had a CAM fail while setting in a Campground. Everything worked when we pulled in, but no brakes when we went to leave. I now carry a spare CAM.

[Titan Guy]

Originally Posted by mhs4771

With GM's it's not so much seeing the trailer connected as it is the Low Resistance of the Magnet Coils. That's where the CAM comes in, it supplies the proper low resistance to fake out GM's (prior to 2017) into thinking it's connected to standard electric drum brakes.
I actually had a CAM fail while setting in a Campground. Everything worked when we pulled in, but no brakes when we went to leave. I now carry a spare CAM.

Just to clarify. 2016 and later GM. GM says do not use a resistor/Cam module. Could cause damage. This truck must be moving to get brakes from the pedal. Sitting still and depressing the brake pedal will do nothing.


Sent from my iPhone using Tapatalk

[RCAircraft]

Originally Posted by mhs4771

With GM's it's not so much seeing the trailer connected as it is the Low Resistance of the Magnet Coils. That's where the CAM comes in, it supplies the proper low resistance to fake out GM's (prior to 2017) into thinking it's connected to standard electric drum brakes.
I actually had a CAM fail while setting in a Campground. Everything worked when we pulled in, but no brakes when we went to leave. I now carry a spare CAM.

I have a 2016 Silverado High Country DWD. When brake problems came up I sent an Email to GM's customer service explaining the issues after the dealer gave up. The next day the GM engineer responsible for designing the tow package and software called me directly much to my surprise. He expressed concern as he was finalizing the 2017 design. As Ron (Titan Guy) noted, the CAM module ( resistor) must be disconnected for proper operation of the EOH disk brakes on my High Country. He also commented that the Titan brake controller was the best of all they have tested in respect to lowest/fastest reaction time. He has called several times over the past year. That is stellar customer care!

[mhs4771]

Thanks for that tidbit, I'll have to remember that if I bite the bullit and order an '18 Silverado, to remove my Cam Module before towing.