No running lights, brake lights or trailer lights work from tow vehicle

[RichHog]

So trying to find out why no lights from the tow vehicle umbilical work on my 72 Safari that’s going through restoration. First should say that the tow vehicle connector works perfectly with my 06 FB LE Safari so the issues lie within the 72 23’ Safari.
When we bought her in last Sept some of the lights worked, one turn signal and a brake light. Now I’m getting nothing. Today I connected my “rally” plug into the trailer that turns on all running lights and nothing happened no exterior lights. The trailer was plugged into 120 v ac, new battery charged, all 12 volt working.

Also I just took out the old Univolt and put in a new Boondocker DC unit and a new ac/dc fuse panel so basically all electrical replaced but all internals in the trailer are good.
Next thing will be to unplug the trailer from shore power and start up tow vehicle connect to trailer and start metering for incoming voltage. Any other clues from you rivit masters?

[Wayne&Sam]

I just went through this with a boat trailer. When ALL lights don't work, it might be the trailer ground.

[TG Twinkie]

IMHO you have 2 problems.
1. Old trailer wiring and fixtures. Probably more to do with bad connections and burnt out bulbs.
2. The trailer 7 way plug is not wired for todays TV's. You must rewire the 7 way trailer plug to match the modern lighting configuration.
The exterior lights have nothing to do with the 12 volt DC system inside the coach.
I would use a battery charger for a power source to troubleshoot the problems.

[RichHog]

Electric brakes worked today towing home.

[prairieschooner]

Check the GROUND!

[RichHog]

Ground coming from the tow vehicle ? There’s a white wire ground connected to 12 v conveyer and a bare wire frying to frame from AC power in.

[Al and Missy]

The negative side of the converter should be connected to the negative of any batteries, the negative buss bar in the power panel, the ground wire from the umbilical, and probably the trailer frame as well. Some trailers use the shell/frame as the return to ground for the lights.

Al

[RichHog]

So the white ground wire that runs from the umbilical to the back of trailer is connected to the ground on the boondocker dc power. Thinking it needs to move to the ground bus bar on the progressive dynamics dc fuse panel. Thoughts?

[Al and Missy]

As I said above, all of the grounds should be connected together somehow - umbilical, battery negative, converter, negative buss bar. If the white wire is the only wire connected to the converter negative, that will allow the converter to charge the TV battery but not provide power to the TT unless that junction is tied to the negative buss bar somehow.

Al

[CBWELL]

Do you have the trailer connected to the TV? Ground between the trailer and TV is through the hitch as well. The 12 volt trailer system does not have anything to do with the running lights, nor does the 120 volt or the power converter. Grounding, or lack of, is likely your problem. The power for the running lights originates in the TV, so must be grounded back throught the TV,

[RichHog]

So inside the trailer the white wire is the common ground and others have said behind the wall it ties into other wires that are grounding points. The service manual (very handy)shows the white going off the old Univolt negative ground to the umbilical cord to tow vehicle. It also shows a breaker under the gaucho near the junction box so I’ll check this out. I’m thinking that the white should come off the convertor ground and move to the negative bus bar in the fuse panel.

[xrvr]

As has been reported before, is your umbilical cord updated to new type?

[RichHog]

To my knowledge no, don’t know if it was original or was updated. The pins seem to match when plugged in. Will take a deeper look at it today. When we first connected it to bring trailer to Texas we got some of the back lights, brake and one turn light to work. Figured the rest was bad bulbs rust etc.

[RichHog]

So got most of the top running lights working, lots of bulbs out. One back taillight works, no brake lights or turn signal lights. Will replace the 7 wire umbilical connecter as suggested and take it from there.

[TG Twinkie]

Originally Posted by RichHog

So got most of the top running lights working, lots of bulbs out. One back taillight works, no brake lights or turn signal lights. Will replace the 7 wire umbilical connecter as suggested and take it from there.

Be sure to ID each of the wires in the U Cord by function. The colors may not match up to todays color standards.
Tail and Marker/Clearance lights are one in the same.
Left and right turn signals use the brake light filament in each fixture.
One circuit for left, one circuit for right.
There will be one common/ ground wire.
One brake wire
One charge line wire.
6 wires total. Unless you have backup lights. Then there will be 7 wires.

[RichHog]

I’ve got a copy of the 72 service manual that shows the wiring. Will see when I take it apart and replace the plug. Thanks for listing the circuits.

[RichHog]

Originally Posted by TG Twinkie

Be sure to ID each of the wires in the U Cord by function. The colors may not match up to todays color standards.
Tail and Marker/Clearance lights are one in the same.
Left and right turn signals use the brake light filament in each fixture.
One circuit for left, one circuit for right.
There will be one common/ ground wire.
One brake wire
One charge line wire.
6 wires total. Unless you have backup lights. Then there will be 7 wires.

Thanks for the details. Replaced the trailer 7 pin plug. Was easy that the plug had the wire colors on each pin so decided to follow that. Was very different from the wiring on the old plug and the diagram in the 72 Service Manual. Only problem, besides some lights out is the white backup lights stay on continuously so not sure how to trouble shoot that. And the left brake light works but not the standards running light. I’m guessing that there are two bulbs in there and one is out. One step closer though.

[TG Twinkie]

Originally Posted by RichHog

Thanks for the details. Replaced the trailer 7 pin plug. Was easy that the plug had the wire colors on each pin so decided to follow that. Was very different from the wiring on the old plug and the diagram in the 72 Service Manual. Only problem, besides some lights out is the white backup lights stay on continuously so not sure how to trouble shoot that. And the left brake light works but not the standards running light. I’m guessing that there are two bulbs in there and one is out. One step closer though.

Are you plugged in to the TV?
Which pin is the white wire connected on the 7 way plug?

[RichHog]

I think the white was the last connected and went to the center pin. Yes was connected to the TV. Think the white in the trailer is the ground wire.

[RichHog]

So after rewiring the 7 pins to match the colors on the plug now the electric brakes do not work. Nothing on the display for the controller and it was working before. Service manual shows Yellow Wire is the brakes. No idea where to more it to.