Great site and thanks for having me. Now on to my issue. I know some think it is a cardinal sin to use a LS as a tow vehicle but per the lexls site it does work and tows very well. However, after three trips with our tiny pop up in tow suddenly my outside rear tail lights are not coming on. The lights on the trunk lid work fine as well as the turn signals and stop lights. The tail light out indicator on the dash is not on either. I have inspected the wiring in the trunk as much as possible without tearing into the major taped up areas. Any thoughts?

 

use a test light and find out if you lost power or ground for starters

 

I did test the wire leading to the tail lights and there is no power. I tested it as far up stream as I could in the trunk.

 

I also removed the Lamp Failure module in the trunk and checked it for melted connections and there were none. I was able to put a test light on the wire that runs to the trunk lid tail lights and of course there was power because those lights work. There is another wire running to the relay that appears the same as the other wire that I tested but it did not have power running to it. Is there separate wires running to that relay for the trunk lid and fender tail lights?

 

what year model is yours
tail lights are running lights, do the brake/stop lights work? turn signals?
and do your trailer lights work (at all)

 

1994 LS400. Love the car.

 

1994 Lexus LS 400 Trailer Wiring >

Separate wiring system - brake and turn signals are sent along separate wires. A powered converter module is required to safeguard the vehicle's wiring and to provide enough power for the trailer lights.

 

The car,s brake lights, turn signals and trunk lid running lights work. Just the four running lights on the back of the fenders don't work. The trailer turn and brake lights work but not the running lights. I used the same trailer wire kit as lexls used on his. Universal trailer wiring harness. All was fine until this last trip. Could the trailers running lights have somehow overloaded the cars wiring?

 

yes, I think so the above shows a powered converter (?) wish I could help more, haven't towed in 20+ years.

 

Thanks so much. I will continue the search.

 

I'd check the tail lights failure sensor unit in the trunk. I have found that the soldering points of the sensing resistor or the connector were not in good condition. Some of them were melted and some boards were burnt. The unit is located as is shown in the link below
https://www.clublexus.com/forums/ls-...ml#post9522843

 

I did check the tail light sensor in the trunk and it appeared to be ok. I may just replace it anyways to eliminate that possibility.

 

Today I had my local mechanic take a look and he feels pretty confident that its the Lamp Failure module. So I just ordered one off ebay. I will let you know what the outcome is after I have received and installed the part.