Trailer Fault/Disconnect errors

[Cate&Rob]

Hi Jim - Connection box installation looks great. (I bought one of these and have it in my “spares” bin). I think you need to measure current draw on each circuit. If one of these is zero (maybe a bad ground) the truck might see this as a “disconnect”.

Just yesterday on another thread, I was conversing with Al about test meters that can measure DC current with an inductive clamp. (Most meters only measure AC current with the clamp). I have had good results with the BlueSeas meter https://www.bluesea.com/products/811...imeter_-_AC_DC but there are others. This will allow you to measure current draw for each circuits (lights or brakes) without disconnecting anything.

This would be a good diagnostic to run before pulling the brakes apart. I think it’s supposed to be 3 amps per brake magnet.

Rob

[TucsonJim]

Good idea on the current check Rob. And that's a good idea too Curtis. The only issue is that it's such an intermittent problem that I could go days without it showing up.

Jim

[Dentil]

Jim,

I see you have a Ford TV, but I had a similar experience with my GMC. I had intermittent "check trailer connection" immediately followed by "trailer connected" on my 2015 GMC / 303rls. It happened when connected to either the in bed or rear bumper connector. I figured the problem was the factory pigtail connector so I ordered a new one. In my online research before I changed out the pigtail and also found several others mentioning this happening on their General Motors TV's. In a bulletin that I found, GM recommended a new ground wire to the frame at the junction box. I talked to my service adviser and he confirmed. I did this along with the new pigtail and it has solved my problem. I will put in quotes below part of the service bulletin that I found online.

Hope you get this resolved,
Dennis

"1.1 Remove the original trailer ground wire (normally white wire) from the trailer side of the 7-pin trailer connector.
1.2 Install a ring terminal (PN 12103512 located in Delphi Tray 18 or equivalent) to this wire and fasten the ring terminal to the metal or aluminum chassis of the trailer using an M6x1x20 self-taping phosphate zinc coated screw (PN 11609540 or equivalent).
• Pre-drill trailer chassis location with a 3/16″ hole.
• Make sure the trailer chassis location is clean of paint or coating material prior to installation.
• Galvanic corrosion between dissimilar trailer and screw metals may require that this ground location be periodically cleaned.
1.3 Obtain a sufficient length of minimum 10 gauge (5.0 mm) white wire and fasten with ring (PN 12103512 or equivalent) terminal to the trailer chassis at the same location as the original ground wire.
1.4 Install and fasten the other end of the new ground wire into the trailer side of the 7-pin trailer connector"

[TucsonJim]

Jim,

I see you have a Ford TV, but I had a similar experience with my GMC. I had intermittent "check trailer connection" immediately followed by "trailer connected" on my 2015 GMC / 303rls. It happened when connected to either the in bed or rear bumper connector. I figured the problem was the factory pigtail connector so I ordered a new one. In my online research before I changed out the pigtail and also found several others mentioning this happening on their General Motors TV's. In a bulletin that I found, GM recommended a new ground wire to the frame at the junction box. I talked to my service adviser and he confirmed. I did this along with the new pigtail and it has solved my problem. I will put in quotes below part of the service bulletin that I found online.

Hope you get this resolved,
Dennis

"1.1 Remove the original trailer ground wire (normally white wire) from the trailer side of the 7-pin trailer connector.
1.2 Install a ring terminal (PN 12103512 located in Delphi Tray 18 or equivalent) to this wire and fasten the ring terminal to the metal or aluminum chassis of the trailer using an M6x1x20 self-taping phosphate zinc coated screw (PN 11609540 or equivalent).
• Pre-drill trailer chassis location with a 3/16″ hole.
• Make sure the trailer chassis location is clean of paint or coating material prior to installation.
• Galvanic corrosion between dissimilar trailer and screw metals may require that this ground location be periodically cleaned.
1.3 Obtain a sufficient length of minimum 10 gauge (5.0 mm) white wire and fasten with ring (PN 12103512 or equivalent) terminal to the trailer chassis at the same location as the original ground wire.
1.4 Install and fasten the other end of the new ground wire into the trailer side of the 7-pin trailer connector"

Dennis - Thanks for the tip. That certainly makes sense, and is right where i'm focused now. As you can see in the attached photo, there is one ground wire going into the frame, which leads to a twist on connector with many other grounds tied in. I've going to install a ground buss as soon as it arrives from Amazon and clean the mess up. After that, I'll start checking the current draw to the brakes as Rob suggested.



Jim

[CoChris]

Check the ground wires in the wire nut and, with a good ohm meter, the resistance to chassis ground. In my new (2 week old) Solitude I had a high (~1.2 ohm) connection from the RV 7 pin connector to trailer chassis ground. In the junction box for the RV cable (under the pin box in my 5er) the local green wire was pulled completely out of the crimp connector. With VERY GENTLE pulling on the other 4 white ground wires one came out of the crimp very easily. I cut off the crimp and reconnected them. One of the remaining three wires had only a few strands of wire in the crimp. Both the local ground (at junction box) and on the chassis (near my battery) had ring terminals just screwed down OVER the painted chassis. Cleaned these to bare metal and reattached the grounds. These fixes gave me a much better (<.2 ohm) but still high ground connection. Poor grounds will lead to many intermittent problems.

Chris

[TheLexx]

Check the ground wires in the wire nut and, with a good ohm meter, the resistance to chassis ground. In my new (2 week old) Solitude I had a high (~1.2 ohm) connection from the RV 7 pin connector to trailer chassis ground. In the junction box for the RV cable (under the pin box in my 5er) the local green wire was pulled completely out of the crimp connector. With VERY GENTLE pulling on the other 4 white ground wires one came out of the crimp very easily. I cut off the crimp and reconnected them. One of the remaining three wires had only a few strands of wire in the crimp. Both the local ground (at junction box) and on the chassis (near my battery) had ring terminals just screwed down OVER the painted chassis. Cleaned these to bare metal and reattached the grounds. These fixes gave me a much better (<.2 ohm) but still high ground connection. Poor grounds will lead to many intermittent problems.

Chris

Hmm, I wonder if this is the problem with mine. Yesterday I was getting a message on my truck dash "Trailer Brake Light Intermittent Fault". I got out and check the rear light as my wife activated the brakes and turn signals, and sure enough the light worked fine. But I kept getting the error message.

[Jims94vmx]

I had a hard time getting my truck to see it was connected.....during the travel I had a left turn signal error and fast blink.....turned off turn signal and it was fine......if it ever gets warm and stops raining or snowing I will check the box also.....

[TucsonJim]

FOLLOW UP. As reported in this and other posts, I did a lot of rewiring to try to resolve the "trailer disconnect " warning.

I've finally determined the cause of the fault. Last year, I replaced the incandescent brake bulbs with LED bulbs. Evidently, the truck didn't like the change. I installed new incandescent bulbs before we departed on our summer journey a couple months ago. We have traveled 2500+ miles and there were no warnings. This morning, I reinstalled the LED bulbs and received the "trailer disconnect" warning just a few minutes later when I applied the brakes.

So I'll just run incandescent bulbs from now on.

Jim

[Jerryr]

Jim. I believe that this adaptor should allow you to use the LED bulbs it provides the additional resistance needed for the TV to recognize the lights.
https://www.amazon.com/57003-7-Way-B.../dp/B00AFVOF3M


Jerry

[Airrace]

Jim, Your ground wire looks like mine. I removed the tape, twisted a little tighter, put 3 zip ties on it and re taped it. Will see what happens next week as this will be my 1st time using a plug in the truck bed.