check trailer wiring warning in TV

[Dave27]

I am getting a "check trailer wiring" warning as I pull the trailer. It started very intermittently. I cleaned the contacts, no change. It is getting more persistent, and annoying. How can I find the source of the problem? We are on the road, so it is difficult to do much of a repair, and I don't want to do something that will prevent power going to the trailer from the truck. I looked at the junction box on the trailer, where the plug to the truck is wired in. What a "rat's nest". I am concerned about pulling it apart and not getting it back together again. But I will if that is necessary, I would appreciate any guidance.

We are on the road escaping a huge winter storm in the north, and running into monsoons in Mississippi. We are heading to Texas, and maybe Arizona, if the warning chimes don't drive me crazy.

Thanks,
Dave

[Gold Country Livin']

Dave,
In short answer, I don't know but this happened to me 2 years ago and only once. Many different possibilities here. Since yours is GM like mine, might be similar.

First, do the brakes on trailer work? Mine was yes. I unhooked the 7 wire trailer connector, and still had the warning light on dash, therefore truck problem. Took to dealer and could not find an issue and no TSB. The indicator light had since gone out though and made it more difficult to get a code.

Also could be broken wire on brake assembly, so do at least, a visual around the brakes of course (could be internal on brakes of course). Then the rats nest under the junction box where wire from truck meets wiring by fifth wheel hitch.

On mine, the problem never surfaced again but I read somewhere that some people traced it back to a problem with the integrated trailer brake controller in the dash (which would explain why it stayed on while trailer was unplugged). On mine, since the trailer lights worked and brakes were normal, I drove it until the destination, but again, never to be solved!

Not much help but obviously check brake function and lighting at least obviously.
Jim

[KamFlyer]

I am getting a "check trailer wiring" warning as I pull the trailer. It started very intermittently. I cleaned the contacts, no change. It is getting more persistent, and annoying. How can I find the source of the problem? We are on the road, so it is difficult to do much of a repair, and I don't want to do something that will prevent power going to the trailer from the truck. I looked at the junction box on the trailer, where the plug to the truck is wired in. What a "rat's nest". I am concerned about pulling it apart and not getting it back together again. But I will if that is necessary, I would appreciate any guidance.

We are on the road escaping a huge winter storm in the north, and running into monsoons in Mississippi. We are heading to Texas, and maybe Arizona, if the warning chimes don't drive me crazy.

Thanks,
Dave

We had this happen with our previous rig. It turned out be one of the splices where the brake solenoids tie into the brake wires at the axle. The splice was rubbing on the top of the axle and had worn through the insulation causing an intermittent short. Drove me batty for about 500 miles!

[Yoda]

I second checking the wiring at the breaks. Had issue with my last unit where the wiring went into and out of the axle to the brakes. Rubber grommet was missing and wiring had shorted, Also found wiring nuts loose where connected to brakes too.

Hope this helps

One other thing to ask, was there water in the junction box (rats nest) at the hitch.

[Dave27]

Dave,
In short answer, I don't know but this happened to me 2 years ago and only once. Many different possibilities here. Since yours is GM like mine, might be similar.

First, do the brakes on trailer work? Mine was yes. I unhooked the 7 wire trailer connector, and still had the warning light on dash, therefore truck problem. Took to dealer and could not find an issue and no TSB. The indicator light had since gone out though and made it more difficult to get a code.

Also could be broken wire on brake assembly, so do at least, a visual around the brakes of course (could be internal on brakes of course). Then the rats nest under the junction box where wire from truck meets wiring by fifth wheel hitch.

On mine, the problem never surfaced again but I read somewhere that some people traced it back to a problem with the integrated trailer brake controller in the dash (which would explain why it stayed on while trailer was unplugged). On mine, since the trailer lights worked and brakes were normal, I drove it until the destination, but again, never to be solved!

Not much help but obviously check brake function and lighting at least obviously.
Jim

The brakes work. I will check the brake wiring when I get someplace dry. And there was no water in the "rat's nest"
thanks,
Dave

[howson]

I am getting a "check trailer wiring" warning as I pull the trailer. It started very intermittently. I cleaned the contacts, no change. It is getting more persistent, and annoying. How can I find the source of the problem? We are on the road, so it is difficult to do much of a repair, and I don't want to do something that will prevent power going to the trailer from the truck. I looked at the junction box on the trailer, where the plug to the truck is wired in. What a "rat's nest". I am concerned about pulling it apart and not getting it back together again. But I will if that is necessary, I would appreciate any guidance.

We are on the road escaping a huge winter storm in the north, and running into monsoons in Mississippi. We are heading to Texas, and maybe Arizona, if the warning chimes don't drive me crazy.

Thanks,
Dave

Hopefully Guest (Jim) sees this--he may be able to provide some insight on what triggers the message in your Silverado.

[Kksfish]

On my previous tow vehicle a 2500 Silverado gasser same thing happened , I pulled into a rest area and called the service manager where I bought the truck and his recommendations after checking the wires at the trailer brakes was to “pack some dielectric grease in the socket”on the truck side, turn the ignition switch off, count to ten,then re-start.
it worked ,the message cleared and I never had another problem............until I purchased a Ram, but that’s another issue!

[Guest]

Hello,

I would start with a thorough cleaning of the trailer and truck connectors (see link below). Also keep in mind the trailer plug itself on the truck is replaceable so you may also want to look at the truck plug/truck harness interface. Do you see any messages when driving without the trailer connected? Are there any DTCs (diagnostic trouble codes)?

If not, you will need to begin looking into issues with trailer wiring if the cleaning does not correct the issue.

https://www.etrailer.com/question-61101.html

[Guest]

Hopefully Guest (Jim) sees this--he may be able to provide some insight on what triggers the message in your Silverado.

Howard,

I can take a deeper look into the actual trigger requirements where for now I would assume the trailer brake controller is looking for a specific range of electrical resistance.

Jim

[howson]

Howard,

I can take a deeper look into the actual trigger requirements where for now I would assume the trailer brake controller is looking for a specific range of electrical resistance.

Jim

Thanks, Jim. For now I suggest we wait and see if the OP comes back with a resolution or continues to have issues.

[KamFlyer]

We had this happen with our previous rig. It turned out be one of the splices where the brake solenoids tie into the brake wires at the axle. The splice was rubbing on the top of the axle and had worn through the insulation causing an intermittent short. Drove me batty for about 500 miles!

I forgot I had this GMC bulletin on my laptop. From what I can recall, the trucks IBC sends a low level pulse down the brake wire multiple times per second sensing the brakes. If that pulse is missed or the return is out of tolerance it fires off the alert.

C1114 diagnostics.pdf

[Guest]

KamFlyer,

Great information. I'm privy to all of GM documentation but I cannot list them publicly unfortunately.
The GM brake control system is very sophisticated and will mostly check circuity on the truck side of the system. However it will also check for issues on the trailer side such as:

Short to Ground
Open/High Resistance
Short to Voltage
Signal Performance

DTCs will be recorded on the following while monitoring the trailer
Battery Positive Voltage
Trailer Brake Control Circuit
Trailer Brake Feedback Signal
Trailer Brake Enable Signal
Trailer - Aux supply Voltage (trailer brake output signal)
Ground Circuit

As in the document you provided, the 7 way connector or issues with the trailer are the most common causes of intermittent "check trailer wiring" messaging. Its also extremely important that if a plug replacement is needed on the truck side, that it is a GM replacement part. On the trailer side ONLY the SAE certified HD Pollak plug is acceptable.

For the OP, I would check the trailer plug interface for being clean and start with the trailer ground as seen on the rats nest pic that Howard provided. Check for DTCs (codes) and you are welcome to send me a PM with that information where I would be happy to help out.

Jim

[gbkims]

I'd read a couple comments on a 2500/3500 Trailer Brake System errors.
One was with a DTC C1117, the brake control switch was replaced.
Another was a short in the wiring from chafing where it runs behind the front fender.
I had this bulletin PIT5509 bookmarked, it's like the one posted above: https://static.nhtsa.gov/odi/tsbs/20...81241-2280.pdf

[Dave27]

Thank you for the suggestions everyone. I cleaned the contacts with an electronic contact cleaner - no difference. There are no fault codes on the truck, the message only comes up when hooked to the trailer. I tried the bumper socket instead of the side one in the truck box, same problem. So I think the problem is on the trailer side. I filled the plug with dielectric grease, same problem. I checked the brake wires, everything I can see outside the wheels looks good.

It is very intermittent. When we started out yesterday morning, there were no chimes for hours. In the afternoon, it would chime once in a while, and sometimes repeatedly for a minute. It did it when it rains, and when it doesn't.

[Canyonlight]

Dave - possibly I missed it in this post but did you take the cover off the junction box under your pin box to ensure that all wires are connected properly as Jim mentioned in post #2 ? Pretty quick and easy to do.

I recall some posts over the years with folks in-advertantly pulling on the RV 7 in connection cord too hard (like forgetting to disconnect from the truck) or just simply having the connections come loose for various other reasons. These could result in certain trailer light functions/battery charging/brakes, etc. not working at times or at all and certainly truck display error msgs. as well.

Dan