No Turn or Brake Lights at Tow Dolly Connector on 2002 Adventurer

[Dionmm]

2002 Adventurer 30gy
SN: 10g62c263401
Vin: 1fcnf53s92oao2461


Had a tire failure on my tow dolly that destroyed the taillight wires.
Replaced both taillights with updated led fixtures.
I now have only running lites . My connector is a 4 pin. Wiring diagram from Winnebago shows a 6 pin connector.
All lighting functions properly on the coach.
Tow dolly will not operate the turn signals, brake lights or flashers.
Checked all fuses and circuit breakers.
Checked and have a good ground.
I’m seeking any advice on where to look next.

 

[bigbAZ]

Did you actually measure for voltage at the dolly tail lights, between the brown and ground with the running lights on and between the yellow or the green and ground while the flashers are on? Do the dolly side marker running lights work? Does the coach have a trailer tow module with fuses?

To rule out the coach, run a test wire directly from the battery to each of the wires on the trailer (except the ground!). If you now have lights, there may be a trailer tow fuse somewhere.

BTW blue is usually for electric brakes, is there a chance you have a white that goes there or does the dolly have brakes?

edit: Looking at the typical 4 pin round setup you may have it wrong..

 

[Morich]

We all tend to develope our own methods over time, so I might throw in what I would do in this situation First I would not work to get power to the trailer but first make sure I have the RV correct. A part of that woud be to not trust the connector wiring at this point but look at each pin and assuming it may not have been wired in any standard way. If it has been changed, I have to assume it may be wrong!
Do you find ground where expected as it runs all the rest? Then do each of the other give you power where it should be? Brake light when stepping on brake, tailight when those are on?
Wiring is simple but can confuse us really bad, so I go one step at a time and getting it to the connector has to be first for me.
If ALL still seem to be a problem, I then choose one single item and find what is wrong there before moving to the rest.
Have you found the correct drawing for Workhorse or Ford and which you have? If the connector on the RV is not right, it is certainly possible that multile fuses on the RV are blown but that info is likely to have to come from the chassis builder as not part of the RV thinking?
I do spot that the connector wiring does seem to come to that plug on different wires than the items on the RV. That seems to mean there are likely other connections, fuses, etc. on the RV to feed power to the connector seperate from the RV items?
Any chance you have not found all the correct fuse panels on the RV? It may be time to search for info on the Workhorse, Ford or which chassis it rides?
I see nothing on the Winnebago wiring to help us there!
It IS possible that any item that was working at the time of the tire problem would blow a fuse as it happened, but I might first want to check the ground side as that seems more likely to kill several different circuits at one time.
But testing works better than guessing!
One of the problems with using the trailer to test is that a problem there can blow a bunch of fuses that you have just replaced and you can go into the fight thinking the fuses are good!

 

[Dionmm]

I measured the voltage at the 4 pin connector on the coach. One oddity: it appears that the ground for the dolly lights comes from the dolly hitch being attached to the coach. Is that a common practice?
I have another fuse box to check for the turn- brake lights.
My pin connector is exactly as shown in the post from bigbAZ.
I found two blown fuses in the last fuse box, replaced, problem solved.
I thank you both for your expertise, time
and guidance. Much appreciated!
I will start a new thread concerning a generator issue.

 

[bigbAZ]

One oddity: it appears that the ground for the dolly lights comes from the dolly hitch being attached to the coach. Is that a common practice?

Well no, but it appears that in order to have brakes on the dolly they ran out of wires on the 4 pin so they grounded it through the ball. Normally a 4 pin is running lts, brakes, signals and ground which takes 4 wires. To do it right they probably should have changed the dolly to a 6 pin.

 

[Morich]

The big problem is that folks do this sort of thing and it creates all kinds of questions for everybody else as well as the lights may go out every time the hitch bounces!
NOT good practice!
You may have seen trailers going down the road with the lights blinking like every time they hit a bump? They should at least run a jumper cable to make a good ground that stays good!

 

[Dionmm]

Morich,
The ground wire on the 4pin connector attaches to the trailer brake controller.
Would you recommend that I add a wire from the dolly frame to the controller ground post?

 

[Bryon Carpender]

Normally the Intrconnector to the trailer,,the white wire ground is usually bonded directly to the Frame chassis of the Trailer, continues through to the lights.
so you have a contious ground if the white wire breaks somewhere alonghe wiring path you can always test to the Chassis

 

[Dionmm]

Currently everything is working properly.
I have added a ground wire attached to the frame of the tow dolly.
Consider this post issue resolved.
Thanks to each of you for your replies and expertise.