No Taillights

JeffGeb

All of a sudden I have no Tail, Brake, Signal, or side lights. Everything has gone black! Is there a fuse that would do just this? I don't think so. I expect it is a bad ground, but I don't know where it would be. Outlet plug from vehicle seems to be putting out juice properly. I have a remote electric brake. I have taken the cord out from it and gone directly to the vehicle outlet, but still everything is black. Ideas?

Sharon_is_SAM

Did the 7 pin get wet?

Grumpy_G

Yes sounds like a ground issue. Try rigging up a temporary ground and see if the lights come back. E.g. use a jumper cable to connect the trailer frame with the vehicle frame/tow hitch. On a 320 you can probably reach the negative battery post and connect to the vehicle. 

Denny16

The taillights’ (towing connection) fuse is in the normally in the tow vehicle (TV) 7-pin wiring connection.  Check that your 7-pin connection on the TV is working.  Use a (military volt/ohm) meter or get a 7-pin tester tocheck the 7-pin connector has 12 VDC at tail light connection.If the TV 7-pin works, then check the 7-pin socket on the TaB is not wet or dirty.  Then check the 7-pin connection at the TaB, under the front, where the frame meets the body, inside a black box.
  

If you have a bad connection somewhere in this area, this will keep the lights from working.  The other connection is in the back of the TaB behind the bunk area/rear locker.  No fuses between the front wiring harness block and the tail lights.
 Cheers 

JeffGeb

Denny16 - Explain what you mean by "TV"

dragonsdofly

@JeffGeb TV in this case is Tow Vehicle. Use of a meter refers to the use of a "multi-meter", a tool which will help determine, and/or detect electrical current flow. The multi-meter can find a "live" or "hot" wire, determine whether a fuse or breaker is allowing electricity to pass through it to farther locations in the electrical circuit, etc. The meter can help you track the working or non working components of your electrical system, determine your neutral and ground legs and find ground outs or short circuits. Most of us consider it an essential tool and always carry one. If you have a multi-meter, @Denny16 is suggesting you first check the 7 pin connector on your Tow Vehicle to make sure that every electrical connection is working, i.e. on, and transmitting electrical current to your t@b trailer. -Denise

MuttonChops

@JeffGeb ;  Information in your earlier forum posts indicate:

+ + + Your Tow Vehicle [TV] is a 2018 Highlander with a 4-pin trailer connector;
           Ground, Left Turn, Right Turn and Stop circuits.

+ + + You then installed some type/brand of 4-pin to 7-pin adapter and had a shop run a +12V Aux
           Power wire from your engine compartment to the 7-pin.

+ + + You have been using the Tekonsha Wireless Brake Controller to manage the trailer braking.

The 2018 Highlander does have a TOWING fuse in the main fuse box.

Web-resources are not clear on what this fuse controls; it is rated at 30A which suggests it was intended for a 7-pin +12V Aux circuit.

There are no other 'trailer fuses' in the available reference material . . . that is the Highlander does not appear to have additional trailer stop light/turn fuses.

Suggest you check the TOWING fuse just to be safe.
Suggest you also inspect/check your 4-pin to 7-pin adapter as that would be a great location for an open ground to occur.

Attached picture shows the TOWING fuse location

Denny16

Thanks Denise, added a bit of clarification on my previous post.
 Cheers