Trailer disconnect message
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5th Wheeling
Joined: Aug 2005
Posts: 34
Likes: 0
From: Reno, Nevada
Trailer disconnect message
2012 F350 has been towing fifth wheel for 8 years. Recently had new brakes put on the fifth wheel. Now I keep getting a “trailer disconnected” message, then later “trailer connected” message. The RV dealer that did the work has thoroughly rechecked all wires and connectors on the trailer. I know the truck is sending 12 volts through the plug to the trailer. My trailer side lights work, as do my emergency flashers. When I step on the brake pedal, the trailer brakes work.
The messages are intermittent.
Does anyone have an idea as to the next step I need to take?
thanks
The messages are intermittent.
Does anyone have an idea as to the next step I need to take?
thanks
Thread Starter
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5th Wheeling
Joined: Aug 2005
Posts: 34
Likes: 0
From: Reno, Nevada
by squeezing the manual brake levers together, which causes the brakes to activate. Having brakes is not the issue, it’s the “trailer disconnected “ message that pops up, then later the “trailer connected “ message…?!
Mountain Pass
Joined: Nov 2014
Posts: 220
Likes: 81
From: Maple Ridge,BC
When I changed the 5'ers brakes from electric drum to hydraulic disc, I received similar messages on the dash before I changed the truck from electric brakes to electric over hydraulic. Might want to check the truck is set up for the correct type of trailer brakes. It's been a number of years since I changed the brakes, so can't remember the exact menu option.
FTE Legend
Joined: Jul 2005
Posts: 65,938
Likes: 1,432
From: Millersville, MD
That is quite different than using the foot brake...different circuity. Insure that the RV plug is making good contact with the TV connector and check for rust inside the TV connector. Do you have electric brakes on the trailer or did you have disks installed ? (Hydraulic)
Hotshot
Joined: Jan 2010
Posts: 10,060
Likes: 491
From: Bristol, TN.
Actually all the RV dealer had to do was pull the break-away and measure the amp draw with the truck disconnected from the fiver. If the draw is somewhere between 12 and 16 (amp draw varies by brake size), the problem is ahead of the fiver, usually at the seven pin given the truck controller was working before the repair. An erratic ground in the seven pin is common. I don't know how the fiver brakes can be working at the same time a disconnected signal is thrown as that should indicate they are off line.
Super Moderator
Joined: Aug 2008
Posts: 37,375
Likes: 1,860
From: Frederick, MD
what about using the bumper 7 pin? does that still give the error message?
Step on the brakes and have someone listen for the buzz at each wheel.
I would be looking closely at the 7 pin, truck side.
Step on the brakes and have someone listen for the buzz at each wheel.
I would be looking closely at the 7 pin, truck side.
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Hotshot
Joined: Jan 2010
Posts: 10,060
Likes: 491
From: Bristol, TN.
Good thought on using the seven pin at the bumper for testing. This problem is not that hard to resolve if someone has a simulator box. Just plug it in, throw the box in the truck with you and go for a drive. If it is the truck seven pin it should be obvious.
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More Turbo
Joined: Jan 2005
Posts: 572
Likes: 37
From: Carthage, Mo
My GN trailer has the same problem. No messages from any other trailers I pull. All new wiring on the GN. I am convinced that I have a magnet that is bad on the trailer. Although I haven't investigated deeper yet, I believe the truck circuit is looking for a certain resistance value that is not always being met. I get the message usually after a stop and I believe it's because the bad magnet shows up when it gets warmer from use. Trailer brakes still work even when truck says it's disconnected.
Hotshot
Joined: Jan 2010
Posts: 10,060
Likes: 491
From: Bristol, TN.
My GN trailer has the same problem. No messages from any other trailers I pull. All new wiring on the GN. I am convinced that I have a magnet that is bad on the trailer. Although I haven't investigated deeper yet, I believe the truck circuit is looking for a certain resistance value that is not always being met. I get the message usually after a stop and I believe it's because the bad magnet shows up when it gets warmer from use. Trailer brakes still work even when truck says it's disconnected.
Steve
Cargo Master
Joined: Feb 2005
Posts: 2,898
Likes: 184
2012 F350 has been towing fifth wheel for 8 years. Recently had new brakes put on the fifth wheel. Now I keep getting a “trailer disconnected” message, then later “trailer connected” message. The RV dealer that did the work has thoroughly rechecked all wires and connectors on the trailer. I know the truck is sending 12 volts through the plug to the trailer. My trailer side lights work, as do my emergency flashers. When I step on the brake pedal, the trailer brakes work.
The messages are intermittent.
Does anyone have an idea as to the next step I need to take?
thanks
The messages are intermittent.
Does anyone have an idea as to the next step I need to take?
thanks
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