Trailer Wiring Fault

[rdlouks]

I am about at my wits end. I have a 2016 F-350 Lariat w/the 6.7 Powerstroke. Everything has been perfect up until last year, I started getting an occasional "Trailer wiring fault" when hauling my fifth wheel (2018 Jayco Pinnacle) Now it is happening more often and when it happens I lose the trailer brakes. (almost rear ended a guy who cut in front of me then stopped short to make a left had turn) Needless to say it has make me very apprehensive and almost afraid to tow my fiver. I have inspected, cleaned, and applied fresh dielectric grease to all the connections under the truck with no improvement. I have an IPA electric brake force meter and discovered something that at least I think is unusual. When I am traveling down the road an apply the trucks service brakes the meter shows power going to the trailer brakes and depending how much force I ally to the service brakes the gain increases. As soon as I come to a complete stop the power suddenly shuts off going to the trailer brakes. If I leave the brake pedal depressed about 5 to 7 seconds later the power returns. Is this common, or do I need to look elsewhere. (I am about to sell both units and buy beer)

[Fyrehuntr]

I had this happen when I had a 2016 Ford F150 ecoboost towing a 2016 Jayco Whitehawk. Did all the same things you mentioned, die-electric grease and checked connections. Finally found there were multiple shorts in the brake wiring on the Whitehawk. Jayco dealer replaced wiring to brakes and I never had a problem again.

[Jagiven]

Do you have the integrated brake controller? A friend has I think a 2016, and went through about 3 integrated brake controllers the first few years he had his PU.

[Camper_bob]

It was on a travel trailer, not a 5er, but I had a similar problem after my wire got pinched. I could barely see the damage from the outside of the cable, but it was enough to cause shorts in the wires inside. Popped a couple fuses under my hood too.

Any chance your wires got pinched somewhere along the way?

Either way, sounds like a short somewhere...

[Fyrehuntr]

My 2016 Ford had the factory integrated trailer brake. It was not a problem with the Ford. It was the brake wiring on the camper.

[RoadrunnerII]

I would be chasing the trailer wiring. First place to look would be the brake wires running inside the axle from drivers side to passenger side. Second place would be the actual plug on the trailer. Make sure it is a snug fit. Make sure the lug on the cap is holding the connector into the socket on truck. Any sign of melted or deforming around the individual connections? Also double check your trailer battery... Make sure its in good shape.
Just my 1/2 cent

RoadrunnerII

[masterarcher]

I am having a similar problem. I have a 2016 Ram 2500 and a Jayco Eagle 336FBOK 5W. I constantly get the messages "CHECK TRAILER BRAKE WIRING" followed by "TRAILER BRAKE DISCONNECTED". I have had the 5W to two different dealers both claiming that the trailer is fine. I took the RAM to three different dealers that told me the system was working to spec. I have a factory installed 7-WAY receptacle in the bed and the bumper. The same message comes up regardless of which one I use. One Jayco dealer replaced the connection cord from the trailer to the truck - but that didn't change anything.

The only thing I can think of now is to replace the receptacles on the truck or sell everything and buy an old VW bus.

[rdlouks]

Since I posted this issue, (no I haven't sold everything and bought beer) I found a corroded splice that connects the 10 gauge main trailer brake wire to the first brake magnet. load tested the complete system and have a reading of 12 amps @12.6 volts for all four brakes. (pulled the brake away cable)

I have not hauled it since the repair, but I will let you know if the corroded connecter was the culprit.

[RoadrunnerII]

Glad you found the problem!

Roadrunnerll

[Marine71-76]

Realize he may have fixed the issue - just letting everyone know what we found. We have a 2008 F450 & never had an issue with our 2007 Cameo. In 2016 we picked up the Pinnacle and 1st major trip was to Virginia Beach, which meant we drove through the Appalachians. Never had a problem until just before the bridge in the Hampton area. Pulled over & made sure we were still connected. Of course, it went away. Just as we were getting to the campground, it happened again. We called the dealer & they suggested we have a mobile unit come out. He did & put a meter on our truck & said it was the truck BUT he never checked the trailer! So we took it to a Ford dealership and they ran it through testing - nothing. On the way back home it got worse but no dealership would look at the trailer because we didn't buy it from them (that really stinks - just saying). We found a horse trailer place that would look at it and the next morning they hooked a board that tested all the wiring - trailer too heavy to lift. Everything fine. But still received the message as we traveled.

We took it to our dealer for warranty work & asked them to check. I just happened to stop by while they were looking at the brakes and the tech couldn't find anything out of the order. I looked over his shoulder & asked about a cable that looked wrong. Turns out one of the cables came loose and wrapped around the axle. One of the clamps that holds the cable to the brake shoe came off.

[Flyrotor]

Originally Posted by Marine71-76

We took it to our dealer for warranty work & asked them to check. I just happened to stop by while they were looking at the brakes and the tech couldn't find anything out of the order. I looked over his shoulder & asked about a cable that looked wrong. Turns out one of the cables came loose and wrapped around the axle. One of the clamps that holds the cable to the brake shoe came off.

For this reason I have learned to do all of my own trouble shooting, change my own oil, fuel filters, brake pads, water pumps, etc. If I can't eventually fix it, then I will succumb to take it to a shop. I wish I could trust more of the shops, but I have learned that is not the case.

Engines, transmissions, drive trains, far over my head, and well I just have to look for the right mechanic through referrals and reviews.

[Jdbuck]

I have a 2016 Chev 3500. I’ve had abs warnings, stabil track warning and trailer brake warnings come on. Sometimes my trailer brakes fail and other times they don’t. Long story short, chev says as the trailer is towed down the road it generates static electricty. That gets sent to the try via the trailer wiring thus causing multiple false codes. The fix is to add another ground wire to the trailer per the chev bulletin. Also use the polllak 7 pin as the receiver in the Trk bed is also a pollak product.

Will try the fix soon. Problem is I can go hundreds of miles with no issues then bam the errors hit��

[rdlouks]

Do you happen to know the number of G.M's TSB that pertains to this issue?

[Jdbuck]

Yes sir, #PIT5311F. Check trailer wiring message and or service trailer brake with DTC C1114. June 29, 2020

[MPD56]

I had this problem with my 2008 and 2015 F350 diesel

There is a recall, and I believe they resolved it by updating the 7 pin trailer connector from 2016.

Road Sault and grime was getting into the connections at the back of the 7 pin connector. The system measures the voltage drop between the brake pin and ground to produce this warning, the grime is enough to drop the voltage.

I

[Jdbuck]

Yet another suggestion chev offered was the receiver plug in the 2016 model is a “pollak”. They suggested to use the same brand 7 pin as the fit would be best.

[Rustic Eagle]

Originally Posted by Jdbuck

Yet another suggestion chev offered was the receiver plug in the 2016 model is a “pollak”. They suggested to use the same brand 7 pin as the fit would be best.

The famous GM "Check Trailer Wiring" fault with GM's Integrated Trailer Brake Controller system on my 2016 Silverado 2500HD gasser has been an issue since purchasing my 2500HD new.

As mentioned the 'fault' will take place while towing thus disabling the trailer brakes from functioning until the fault clears itself (Trailer Connected), which could be 1 second to 5 minutes fault delay.

I went camping a couple weeks ago and during the 200 mile trip (each way) I lost my trailer brakes at least twenty (20) times each way

Last year I installed GM's recommended Pollack brand 7-pin connector, along with a new 7-wire harness........, didn't resolve the issue.

I now plan to remove (per GM) the existing trailer ground wire attached at my new Pollack connector and replace it with a new "10 gauge" ground wire. Apparently many 7-pin wire harnesses come with 14 gauge or 12 gauge ground wires....., GM wants 10 gauge.

Basically I plan to follow GM's TSB PIT5311F (link below) as stated, and hope to have the new 10 gauge ground wire installed during the next week. I even purchased GM's recommended grounding screw (PN 11609540).

I will take my TV/TT for a test tow once the new ground wire is installed and report back.

The following TSB lists the vehicles effected from 2014 thru 2020:

https://static.nhtsa.gov/odi/tsbs/20...78359-9999.pdf

Bob

[Marcm157]

Put me in coach - I had the exact same problem towing with my 2016 F150 but as others have said my issue was located in the trailer brake wiring. Didn't appear until almost a year into ownership...

[Rustic Eagle]

UPDATE:

I incorporated all the GM recommended trailer "fixes" identified in their latest TSB (post #17), and still didn't resolve the persistent "Check Trailer Wiring" alert including loss of trailer braking.

Truck now scheduled next Tuesday at local GM dealership for some serious diagnostics.

New Pollak heavy duty 7-wire harness which includes a 10 gauge ground wire, new Pollack male 7-pin connector......., then created a new independent ground wire connection point next to the junction box for the trailer wire harness 10 gauge ground wire (in lieu of being part of a wire-nut/ground wire cluster inside the junction box).





Dedicated trailer harness ground wire.....



Bob

[hankb11]

I had the same problem on my 2015 GMC. I changed the brake control switch circuit board DORMAN 601-226. I also changed the trailer brake control module behind spare tire. Haven’t had the check trailer wiring fault come on since.