Trailer brake module failure?

[David Langford]

Bit of a strange one here. But, I've towed 2 different travel trailers in the 3+ years I've owned my 1500 Hemi 8-speed 3.92, and this has never happened. Towing my travel trailer (2022 Grand Design Imagine 2670MK) from Vegas to Yerington (about 360 miles), 1/2 way there, suddenly get a dash message "Check trailer brakes". Funny thing is that at the exact same time, cruise control stops working, and I get the stability control light on the dash (not the traction control off light, which looks similar). I thought I blew a fuse, didn't have my multimeter with me, or an extra 30 Amp fuse (the trailer brakes are on MCASE fuses). Anyhow, was able to swap it with the one for the inverter since they're the same fuse and same amperage. Hooked back up after our weekend, and things were good, so I figured it was blown fuse. 99% of the way home, same thing happens. This time, I had cruise engaged, and it shut off along with the stability control light coming on, and the message. I thought, dang it, fuse again. But when I got home, I checked the fuse with my multimeter, and it isn't blown. I threw the 1st one away, thinking it was blown.

Any thoughts on if it is something with the brake controller in the truck or the brakes on the trailer or something else? I don't know how those systems are related (or if they even are) The trailer is brand new, I've towed it 10 times or so, and only had issues this time. Hoping that if there is an issue, it's the truck because the dealer is 3 miles away, the trailer dealer is an hour away.

It's apparently intermittent, as it happened when driving on level ground at highway speeds (65 MPH is where I had cruise set). It was hot, over 100 Degrees. I had an eye on all my temps, and everything there looked within normal ranges. Had no other issues with the truck's performance.

 

[csuder99]

"Check trailer brakes" typically comes on when the brake controller does not sense the brakes being present anymore. As the truck has trailer sway control this "upsets" the stability control and it warns that it won't work without the trailer brakes. How that relates to the cruise control I have no idea.

Check the trailer brake wiring, if there is a bad/high resistance connection it throws off the brake controller.

 

[Loudram]

I believe any warning light like that including the check engine light will shut the cruise off. That's the way it's programed.

 

[turkeybird56]

OK, U will find that a lot of times U can lose trailer brake connection. The culprit is how the 7 pin is configured and wired in, just in my opinion not a great design. I have the same issue on MY 19. I cannot hook up cable if truck on, have to turn off and get it to sleep, or I run the chance of blowing 20 amp fuse, in my case running lights. But, I have found that the 7 pin adapter gets worn, loose and one way to help is to attach a bungee cord to the connection to help keep it plugged in and level, when they start moving, you can sometimes lose connection, they will wiggle loose. Also, I had an issue where I used an adapter for years with my wife's F 150, and on MY 15 ED. Well, when got MY 19, plugged in, and got intermittent connection. Adapter was worn and not plugging in securely. Just all the things I have personally found. Not sure if it is your issue or not, just wanted to put info out there. ALL here IMHO ..........

ADDED: OP, U may also want to check the 7 pin on the truck and make sure it is tight/connected to the truck securely also.

 

[turkeybird56]

I believe any warning light like that including the check engine light will shut the cruise off. That's the way it's programed.

YUP. Especially MIL.

 

[David Langford]

I believe any warning light like that including the check engine light will shut the cruise off. That's the way it's programed.

Thank you, that makes sense.

 

[David Langford]

"Check trailer brakes" typically comes on when the brake controller does not sense the brakes being present anymore. As the truck has trailer sway control this "upsets" the stability control and it warns that it won't work without the trailer brakes. How that relates to the cruise control I have no idea.

Check the trailer brake wiring, if there is a bad/high resistance connection it throws off the brake controller.

That makes sense about the sway control. Sounds like I'm troubleshooting a short. Probably going to replace the 7-pin connector on the truck side to, and lube the plug up with some dielectric grease.

 

[David Langford]

ADDED: OP, U may also want to check the 7 pin on the truck and make sure it is tight/connected to the truck securely also.

Yeah, I happen to have a new spare OEM plug, so I'm going to replace that too. Trailer is at storage, so it's kind of a PITA to work on it, but going to look for something obvious like a short. But, it's so intermittent it's likely not that. Got a buddy that has an enclosed car hauler too that I'm going to borrow and see if it does the same thing. If it carries from trailer to trailer, its the truck, if not, it's the trailer. Thanks for the reply.

 

[2003F350]

"Check trailer brakes" typically comes on when the brake controller does not sense the brakes being present anymore. As the truck has trailer sway control this "upsets" the stability control and it warns that it won't work without the trailer brakes. How that relates to the cruise control I have no idea.

Check the trailer brake wiring, if there is a bad/high resistance connection it throws off the brake controller.

Very likely this right here - it is likely a short or bad ground in the system. I occasionally get it with my flatbed trailer, I NEVER get it with our travel trailer. Likely because I am usually pulling/moving the flatbed 2-3 times a month during the summer and once a month in the winter, whereas the travel trailer goes on 3-4 trips a summer and is in storage for the winter.

On a side note, it relates to the cruise control as an attempted 'safety' system. It's more to alert the driver that something is wrong and needs attention, if you are having to control your speed you're more likely to be focusing on driving instead of phone calls or messing with your kid in the back seat.

 

[David Langford]

Very likely this right here - it is likely a short or bad ground in the system.

That's where I'm going first. I have a replacement OEM 4/5/7 pin connector that I'm going to replace anyhow (my marker lights are on all the time), so I already suspected the connector, especially considering it's a brand new trailer. When I get the alert, the marker lights stay on though. If it was a ground issue, wouldn't those go out too? Turn signals keep working too.

 

[csuder99]

The crux with ground issues on trailers is that the trailer hitch connection can act as an intermittent ground. Given that the problem came with the new trailer I'd suspect an issue with the trailer itself. I'd start with the plug itself and typically there is some sort of distribution box under the front of the trailer where the cable goes into.

 

[1970Pelle]

You are using the factory electric brake wiring? It has a blue wire for the electric brakes correct? And you have it hooked up to the add on brake controller?
If you have answered yes. To any of the questions. Pull the cluster and look for a burnt CKT.

 

[2003F350]

That's where I'm going first. I have a replacement OEM 4/5/7 pin connector that I'm going to replace anyhow (my marker lights are on all the time), so I already suspected the connector, especially considering it's a brand new trailer. When I get the alert, the marker lights stay on though. If it was a ground issue, wouldn't those go out too? Turn signals keep working too.

Not always, and not with an intermittent loss. On my flatbed it will occasionally lose trailer brakes but I'll have my running lights and one turn signal. Or I'll sometimes have everything, other times nothing. I actually have everything to completely rewire/relight the trailer, I just haven't had time to do it this summer.

When you're on the road every other week for work, weekends are usually filled up with other pressing projects or family time.

 

[David Langford]

You are using the factory electric brake wiring? It has a blue wire for the electric brakes correct? And you have it hooked up to the add on brake controller?
If you have answered yes. To any of the questions. Pull the cluster and look for a burnt CKT.

Factory wiring in the trailer, factory brake controller in the Ram (I have the trailer tow package on my 1500).

 

[1970Pelle]

The issue I think your having is the truck factory wiring and smart instrument cluster. When you installed the trailer brake controller, you used the supplied harness. This harness wires up to your provided controller, and then plugs into the trucks wiring harness. Correct?
Now I'm not looking at a service manual right now. But the way the trailer tow package is wired into the vehicles wiring harness. It goes through the cluster. And so the brake CKT is to much for the cluster to handle, and it fails in the brake CKT. Because the cluster watches brake pedal position, for several reasons cruise control on and off, ABS brakes, PRNDL switch, and trailer brakes.

What we did for a fix was do not wire the blue wire from the truck to your trailer. Run a stand alone wire, its very own CKT from the battery to the controller. Then straight back to your trailer connection. So the truck doesn't have to bare the load of the trailer brake voltage draw. Who cares if the PCM or BCM see trailer brake. It will think your towing a lite duty trailer with no electric brakes.
But you may have to replace the cluster if there are operating issues from the damaged CKT's. Now please remember I'm going on past vehicle expereance. And I don't have your truck in front of me. So all this is just suggestion, food for thought. And I hope it helps or gets you close. I wish I could jump in a jet and come help. Being retired I have plenty of free time. Good luck. Ken

 

[2003F350]

The issue I think your having is the truck factory wiring and smart instrument cluster. When you installed the trailer brake controller, you used the supplied harness. This harness wires up to your provided controller, and then plugs into the trucks wiring harness. Correct?
Now I'm not looking at a service manual right now. But the way the trailer tow package is wired into the vehicles wiring harness. It goes through the cluster. And so the brake CKT is to much for the cluster to handle, and it fails in the brake CKT. Because the cluster watches brake pedal position, for several reasons cruise control on and off, ABS brakes, PRNDL switch, and trailer brakes.

What we did for a fix was do not wire the blue wire from the truck to your trailer. Run a stand alone wire, its very own CKT from the battery to the controller. Then straight back to your trailer connection. So the truck doesn't have to bare the load of the trailer brake voltage draw. Who cares if the PCM or BCM see trailer brake. It will think your towing a lite duty trailer with no electric brakes.
But you may have to replace the cluster if there are operating issues from the damaged CKT's. Now please remember I'm going on past vehicle expereance. And I don't have your truck in front of me. So all this is just suggestion, food for thought. And I hope it helps or gets you close. I wish I could jump in a jet and come help. Being retired I have plenty of free time. Good luck. Ken

He didn't add a brake controller. It was factory installed when the truck was built. I doubt it's an issue with the truck in all honesty, since it showed up with this new trailer.