Rear lights out after plugging in tow dolly

ZimBob · 10-08-2021, 02:05 PM

Plugged in the new tow dolly today and the back lights in the RV now no longer operate. The lights on the dolly still work, as do all the lights in the front and inside the rig. Just the rear brake lights, turn signals, safety light on top of the rear end cap, etc., are all out.

Most likely blew a fuse when I plugged in the tow dolly.

My question for the forum: anyone know where the fuse is for that set of lights?

I'm in a 2021 Adventurer 29B, so on the newer F53 chassis.

Many thanks in advance for any pointers or guidance (including how I can avoid blowing the fuse again once I replace it). Much appreciated!

ZimBob · 10-09-2021, 06:41 PM

After reading a lot of fuse schematics, I finally gave up and called the selling dealer. Their guidance is that my problem isn't a fuse; rather, it is likely a wiring harness that connects power from the chassis to the rear lights in the motorhome. The plug has been come loose or damaged and needs corrected.

They recommend that I take the motorhome to a local Ford commercial service center. Nearest one to me is about 10 miles away and is closed over the weekend. Will call them on Monday and advise on the outcome.

Bones2003 · 10-09-2021, 07:39 PM

ZimBob, you can download the wiring diagrams from the Winnebago website under Owners Resources. Here is a link: https://www.winnebago.com/Files/File..._f29b_wire.htm
(note there are different drawings based on your serial number)

I think there is a 6-pin wire harness supplied by Ford that comes from the chassis and then a 6-pin harness supplied by Winnebago plugs into that at the back of your coach. That 6-pin harness goes to the stop/turn/taillight/license plate light, and the elevated brake light. Do any of these light work? If that harness got disconnected, then none of those lights would work. I think the marker lights at the top of the rear of your coach are on a different harness but not positive about that. You should be able to find where those are connected by looking around the chassis frame and hitch area under your coach on the driver's side. Ford might tell you it is a Winnebago problem and Winnebago might tell you it is a Ford problem.

Bones2003 · 10-09-2021, 07:45 PM

ZimBob, also there is a fusebox located under the dash by the driver's left foot. It looks like separate fuses for each of those circuits so unlikely (but still possible) that all those fuses are out. I suppose it could be possible that there are connectors located around that fuse box that have come loose.

BobC · 10-10-2021, 07:53 AM

I think the dealer is right. I would think that the dolly lights operate off the same circuit as the MH lights so I don't see how it could be a fuse, since a bad fuse would disable both the MH lights and the dolly lights. My guess is that there's a "Y" in the circuit feeding the MH tail lights and the trailer socket, one branch going to the MH lights and the other to the trailer socket. Most likely, the branch connector feeding the MH lights has come disconnected while that feeding the trailer socket is still intact. Alternatively it could be a bad ground connection for the MH lights, the trailer socket having its own, separate ground.

In either case, unless you can see a loose connector, I'd let the dealer/Ford deal with it under warranty.

ZimBob · 10-10-2021, 10:45 AM

Quote:

Originally Posted by BobC

In either case, unless you can see a loose connector, I'd let the dealer/Ford deal with it under warranty.

This was the answer. I climbed under the back of the rig this morning and found an unplugged connector. Re-plugged it, and all was well.

Love this forum - many thanks to BobC and the rest!

BobC · 10-10-2021, 11:33 AM

Yea!! A simple fix.