Lost Running Lights Mid-Drive

[LiveStreamn]

2018 Tommy Bahama 19

2015 Jeep Grand Cherokee w/factory tow

90 miles into a 200 mile drive I lost my rear monitor connection. Looked out to see no running lights.

Checked 7 pin connector...ok.

Checked TV fuses...ok.

Brakes and turn signals work.

Ideas?

[Al and Missy]

Running Lights are on a different wire. Turn signals double as brake lights. Running lights are the same wire as tail lights. Do tail lights work?

Al

[LiveStreamn]

Tail lights are not working either.

[Lara Me]

Do you have vehicle lights set to auto? Try setting them to always on. They can turn on and off on auto and it triggers the running lights

[Mollysdad]

Originally Posted by LiveStreamn

Checked 7 pin connector...ok.

I assume you checked the 7 pin on the tow vehicle? How?
The tail/running lights is the brown wire in the harness.
Can you get access to the trailer harness to see if the juice is getting there?
Also, make sure the plug is firmly seated in the receptacle. Mine was latched, but nothing worked until I gave it a firm wiggle.

[Jim Flower]

Nice drawing. All those connections have to be clean. I use a small file to touch them up periodically. Confirm operation with a circuit tester on the Jeep end first. Jim

[tjdonahoe]

Check al your grounds

[keweenawbee]

Unplug & spray some WD40 on the connectors.

[AldeanFan]

Is there a fuse in the trailer for running lights?
My ‘77 has fuses in the trailer for the running and brake lights, not sure if the new ones have the same.

[Bob Peahl]

This happens on our RAM if the headlights are set on auto. The trailer lights work as long as the headlights are on. But if the environment lightens, the headlights turn off and take the trailer runners with them. Setting our TV light to ON works.

[Jekerrville]

Don’t know about Jeep products, but you mentioned “factory tow”. I will assume that means not only factory town at fowpulling trailers, but also brake controller and tail and clearance lighting.

If this a good assumption, check under the hood for a fuse box that contains a set of slave relays that work the trailer lighting. There is usually a set of fuses for turn signals, backup lights and tail and clearance lights. You may have a blown fuse for tail&clearance lighting.

This setup is the same in FoMoCo carry all vehicles. Also, slide back the hood cover on the 7-way plug. The screws that’s retain the wiring have a bad habit of becoming loose. Ground wire especially because it is the center contact and uses a little set screw.

Hope this helps.

[LiveStreamn]

Update. Got into the fuse box and pulled the fuse for the tow taillights. It was 20 amp. Of course no 20 amp to be found. Threw a 30 on it and it lit up like a Christmas tree...then after 30 seconds no lights.

So a short somewhere I think. No idea where.

How do you go about popping the cover off the seven pic connector?

[Jekerrville]

The 7 way has two screws. One is large flat blade screw with captures the wire from the trailer to the 7 way plug. Back it off far enough such that the wire is movable. Slide back and fourth into the body of the 7-way connector.

Careful not to back it off to far or it will fall out and bounce and roll to a point mid way under the trailer of Jeep so you can crawl under the vehicle to get it

Next, look on the body of the 7-way connector itself. There is a very small little screw on the blade connection end. That screw needs to be taken out, Phillips head,, completely.

Warning, that screw will not just bounce under the vehicle, but will shape shift into another universe never to be seen by human eyes again.

Now slide the connecting wire toward the end you just took the small screw out of. The entire guts of the connector will be exposed.

Bet you a cup of coffee that a wire is shorting out against another and causing the fuse to blow.

There may only be a little stray strand of wire otherwise it will be completely loose.

Put it back where it is missing and button everything back in place, after you found the screws that bounced away.

While your in that housing, tighten up any other screws on the 7-way that may also be thinking of coming lose.

I usually put a shop towel under where I am working to catch the little buggers to slow down their escapes.

Hope this helps.

[LiveStreamn]

Originally Posted by Jekerrville

The 7 way has two screws. One is large flat blade screw with captures the wire from the trailer to the 7 way plug. Back it off far enough such that the wire is movable. Slide back and fourth into the body of the 7-way connector.

Careful not to back it off to far or it will fall out and bounce and roll to a point mid way under the trailer of Jeep so you can crawl under the vehicle to get it

Next, look on the body of the 7-way connector itself. There is a very small little screw on the blade connection end. That screw needs to be taken out, Phillips head,, completely.

Warning, that screw will not just bounce under the vehicle, but will shape shift into another universe never to be seen by human eyes again.

Now slide the connecting wire toward the end you just took the small screw out of. The entire guts of the connector will be exposed.

Bet you a cup of coffee that a wire is shorting out against another and causing the fuse to blow.

There may only be a little stray strand of wire otherwise it will be completely loose.

Put it back where it is missing and button everything back in place, after you found the screws that bounced away.

While your in that housing, tighten up any other screws on the 7-way that may also be thinking of coming lose.

I usually put a shop towel under where I am working to catch the little buggers to slow down their escapes.

Hope this helps.

I love the satire...keep it coming.

The factory 7 pin has no screws...but the new one I put on does. Now I am trying to figure out which wire does what as the schematics don’t match.