Trailer brake message

Hmm the diode should fix the issue by not allowing the higher voltage from the trailer batteries to get to the truck.

If you disable the solar charger does it fix the issue? If not then something else must be causing the issue.
 
The service bulletin is pretty clear, and GMC has said, if customer comes in with this complaint, a known problem, replace it. If the dealer is clueless, maybe you have one near that will do it.

They won't replace mine because it's an early 23. Really starting to tick me off.
 
I got rid of my GMC but the fix for me was to install a one way diode on the charge lead from the truck so the camper voltage can’t feed the 14.4V to the truck which is what confuses it and shuts off the brake controller. No issues since doing that for quite a few trips. I have an F350 now and it complains that the trailer is not charging. lol.

I had the tailgate issue on my GMC where it came down randomly while driving if it’s raining hard. Supposedly my truck was one of the ‘good’ ones, but clearly it was not. That and all the stupidity to flat tow it behind my motorhome was enough to get me to trade it …
So what did you get?
 
Hmm the diode should fix the issue by not allowing the higher voltage from the trailer batteries to get to the truck.

If you disable the solar charger does it fix the issue? If not then something else must be causing the issue.

The thing that really bites is that it didn't happen with the 18 2500 Ram gasser that I got rid of for this one. Not a happy camper especially when I'm not taking a chance going out for the weekend not knowing whether it's going to work from one minute to the next.
 
The thing that really bites is that it didn't happen with the 18 2500 Ram gasser that I got rid of for this one. Not a happy camper especially when I'm not taking a chance going out for the weekend not knowing whether it's going to work from one minute to the next.

I feel your pain, I had a new '16 Chevy 2500 with my last trailer and would get the "service trailer" on the DIC. Not a fun thing to see going down a hill in traffic with a loaded trailer. Ultimately after a number of visits to the dealer, including with the trailer, a tech found the trailer plug on the truck had some internal corrosion after opening it up, replaced it with a new one, loaded it with di-electric grease, and never had an issue afterwards.
 
I feel your pain, I had a new '16 Chevy 2500 with my last trailer and would get the "service trailer" on the DIC. Not a fun thing to see going down a hill in traffic with a loaded trailer. Ultimately after a number of visits to the dealer, including with the trailer, a tech found the trailer plug on the truck had some internal corrosion after opening it up, replaced it with a new one, loaded it with di-electric grease, and never had an issue afterwards.

I bought the truck last year january, I had them check it out at the end of the season last year, i've put the dielectric grease on everything, did the diode the module from pullrite for the hydraulic actuator. I'm at my witts end.
 
I got rid of my GMC but the fix for me was to install a one way diode on the charge lead from the truck so the camper voltage can’t feed the 14.4V to the truck which is what confuses it and shuts off the brake controller. No issues since doing that for quite a few trips. I have an F350 now and it complains that the trailer is not charging. lol.

I had the tailgate issue on my GMC where it came down randomly while driving if it’s raining hard. Supposedly my truck was one of the ‘good’ ones, but clearly it was not. That and all the stupidity to flat tow it behind my motorhome was enough to get me to trade it …

Did you experience the same brake controller issue on the F350 before installing the diode? I have a ‘22 F350 and have been trying to figure out for the last week why I have no brakes on my ‘24 momentum with 8K axles and disc brakes. Trailer wiring appears to be fine. Pulling the emergency break away locks up the brakes. Trailer wiring pins out fine. Just had the truck at the dealer for two days and they say everything is fine with the truck. Trailer does have the new solar/lithium package in it. Will play around with turning of the solar controllers tomorrow. That is a pain in the butt though with how they are installed in my unit. About to drive through Colorado though… so got to figure out this brake issue.
 
Did you experience the same brake controller issue on the F350 before installing the diode? I have a ‘22 F350 and have been trying to figure out for the last week why I have no brakes on my ‘24 momentum with 8K axles and disc brakes. Trailer wiring appears to be fine. Pulling the emergency break away locks up the brakes. Trailer wiring pins out fine. Just had the truck at the dealer for two days and they say everything is fine with the truck. Trailer does have the new solar/lithium package in it. Will play around with turning of the solar controllers tomorrow. That is a pain in the butt though with how they are installed in my unit. About to drive through Colorado though… so got to figure out this brake issue.

As of right now since we've had the disc brake kit installed on the trailer of which it was set up without the module for the RAM that we had but now have the gmc, I've had the truck and trailer down to the gm dealer and they did replace both trailer modules with no success we have added the diode up at the beginning of the trailer cord, attached the module for gm's and fords replaced the cord and installed a better junction box on the trailer. when the new cord and box was added the module was taken off and just like when it was on i would get to the same point on the road and the brakes disconnected. And it seems when I stop it would reset itself if i'm lucky. No rhyme or reason as to why it is acting like it is. A total pain and we still have got out in it this season yet because i'm afraid as to when it might disconnect the brakes.
 
Did you experience the same brake controller issue on the F350 before installing the diode?

I have not removed the diode and had no issues with the F350 other than it saying the trailer was not charging but that’s not an issue because it has solar and it is getting power. I plan to remove it but just haven’t gotten around to it. Maybe I should leave it in there now :)
 
I have not removed the diode and had no issues with the F350 other than it saying the trailer was not charging but that’s not an issue because it has solar and it is getting power. I plan to remove it but just haven’t gotten around to it. Maybe I should leave it in there now :)

Did take off the module that is supposed to be attached to the pump for fords and gm's and the diode is still on there I think. I had a cutoff switch for the solar put on but it didn't make any difference. I'm looking at putting a new dash brake controller on the truck just in case that might be having issues cause if it goes out, as soon as I stop it seems to come back. I'm just running out of parts to change and very frustrated.
 
Hmm, that is quite annoying yes. Yours is a fifth wheel right, not the travel trailer like mine? Mine had a solar cut off built in so it was easy to flip that off when I initially had the issue in Miami and it did fix it. However part of the problem for me with the GMC was that if the voltage was over 14V it would cause the trailer brake controller to fail. So it did not matter if it was due to charging via solar or some other means. ie: pulling it directly from shore power if it was bulk charging it could also trigger the issue as it would take a few minutes for the battery voltage to settle down to 13.6V.

For me other than making sure the battery voltage was low enough, the diode we installed was inside the junction box where the 7-way cable attaches into the trailer. Is that where they put yours? What diode did they use? It needs to be one of those beefy ones. This is what I used:

https://www.amazon.com/gp/product/B007HRO4X8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
 
Hmm, that is quite annoying yes. Yours is a fifth wheel right, not the travel trailer like mine? Mine had a solar cut off built in so it was easy to flip that off when I initially had the issue in Miami and it did fix it. However part of the problem for me with the GMC was that if the voltage was over 14V it would cause the trailer brake controller to fail. So it did not matter if it was due to charging via solar or some other means. ie: pulling it directly from shore power if it was bulk charging it could also trigger the issue as it would take a few minutes for the battery voltage to settle down to 13.6V.

For me other than making sure the battery voltage was low enough, the diode we installed was inside the junction box where the 7-way cable attaches into the trailer. Is that where they put yours? What diode did they use? It needs to be one of those beefy ones. This is what I used:

https://www.amazon.com/gp/product/B007HRO4X8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Yes it is where they put it. I just messaged him to see if the one you put in was the same kind or not. Plus when the brake kit was added we had a RAM at the time so the instructions for the pump are a little different for the GM's.
 
Well it looks like my saga has ended. After getting the two truck brake modules, the truck brake controller, the trailer power cord and even an updated junction box replaced, trying the diode and the module for the electric over hydraulic pump, it looks like the emergency brake disconnect switch had a short in it. Sometimes I couldn't get 2 miles down the road before it would disconnect but the 40 mile trip from the dealership finally resulted in zero disconnects. Better late than never in getting out with the trailer.
 
iG9CbmG.jpg


On GM trucks remove the TRL BATT CHRG fuse. On our 2024 it was 30 AMP fuse in the #83 position in the fuse box. Your truck may vary the location.

We experienced total trailer brake failure AFTER the GM brake module recall.
Trailer brakes were working fine before. It's terrifying with a 22.000 lbs trailer.

I past years, these fuses used to be found in a plastic envelope in the owners manual on GM built trucks and you installed it if you wanted the truck to charge the trailers battery.

Now the fuse is installed at the factory and power from your trailers solar power system is back-feeding corrupting the Trailer Brake actuator circuit board.

That circuit is now redundant and unnecessary with your trailer solar power. All it does is charge your trailer batteries from the truck, nothing more.

Yes we notified GM and they are deflective and ambivalent to the issue.
Our Grand Design dealer recently discovered this fix as well and a few people I found online.
 
If considering changing double blade plug try this on the trailer (compatible with truck connection):

POLLAK 12-706 Plastic Blade Style 7-Way Plug​

Seems to be a more positive connection.

Recently made this change on a 2019 Ford and non-GD TT, after having many random warnings (brakes, trailer connection, trailer wiring, ...), a lot of trouble-shooting and sometimes no trailer brakes for over a year. This is popular on Airstream forum. There are videos for installation on web.
 

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Well, I am still having this issue. Been to the dealer twice now. When I get home fro this rondo vue I will take it back for the third time. I decided to disconnect my solar panel once before traveling and that didn't work. So assuming I was wrong on the solar disconnect, I went to HD and bought a large box along with duct tape, and covered my panel. I actually thought that was the fix, because evrything was well for around 200 miles. Then it starts all over again. Check trailer wiring, Trailer brakes coneccted and the annoying chime, over and over again.

The bad thing is when the trailer brakes don't reconnect and you need them. I've run into that a few times now.

The dealer has replaced the module and the wiring for the plug.
 
The solution I ended up using was putting a large amp diode in the trailer wiring box so that the battery voltage is unable to feed back into the truck if its higher than the truck voltage. Since that is not needed if the charge is high due to solar charging or full batteries. Then if you are driving all night and the batteries are getting depleted when they get low enough, the truck will charge them up.

I since sold the GMC and got a ford, and now it complains that the trailer is not charging. LOL. But it does charge if the trailer battery is low.

This is the diode I used and it worked great. Never had the issue again:

 
iG9CbmG.jpg


On GM trucks remove the TRL BATT CHRG fuse. On our 2024 it was 30 AMP fuse in the #83 position in the fuse box. Your truck may vary the location.

We experienced total trailer brake failure AFTER the GM brake module recall.
Trailer brakes were working fine before. It's terrifying with a 22.000 lbs trailer.

I past years, these fuses used to be found in a plastic envelope in the owners manual on GM built trucks and you installed it if you wanted the truck to charge the trailers battery.

Now the fuse is installed at the factory and power from your trailers solar power system is back-feeding corrupting the Trailer Brake actuator circuit board.

That circuit is now redundant and unnecessary with your trailer solar power. All it does is charge your trailer batteries from the truck, nothing more.

Yes we notified GM and they are deflective and ambivalent to the issue.
Our Grand Design dealer recently discovered this fix as well and a few people I found online.
Correct me if I am wrong on this, after pulling the fuse, anyone with a residential frig and the factory 300W solar would not have enough battery to keep the frig going after several hours. I get that if you have sufficient solar, or not driving at night, this is a good temp solution, but not the permanent one. The diode solution is the only reliable one until GM figures it out in a year or two.
 

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