I have a problem with the factory installed trailer wiring harness on my 92 4runner. It is not the trailer, I checked it out with the wifes minvan. The right side trailer turn signal and brake light does not work. I know that because the 4runner has separate turn and brake lights that there must be a conversion box of some sort somewhere in the truck. It looks like a factory install. Can anyone help me out? I really do not want to continue to tow my boat with the wifes minivan. You can see the seriousness of my situation. The harness wires (3 each) originate from the right rear inner fender if that helps any..Thanks..

 

1st thing that comes to mind is a ground problem. The set-up COULD have a ground on ea. leg of the run. (@ ea. tail light) I would suggest following the wires as best you can, look for a damaged or broken grnd. wire.
My 95 has a factory set-up too but I've had no problems.

 

Tried that. I actually cut the wires from behind the receiver connector and checked with a meter. There is no signal from the right tail/brake lead. Used my own ground too. Wires look good but I am going to check again. I am a B-52 electrician so I get quite a bit of practice chasing wiring problems (40 year old aircraft). I believe that there has to be a converter for the brake/turn signal thing. I just don't know where it is and I do not want to tear apart the interior panels looking for it. Thanks

 

It will be interesting to hear how it turns out.....I have the same problem--always thought it was my boat---tried to get toyota to fix it for free at 38k

 

Well, I found it. There was a conversion box and it was located behind the right rear interior panel. The box itself was bad. It was the same one that you can buy at any autoparts store that takes care of the amber turn signal issue. It did not look very factory. Put in a new box and all was good. BUT, and I will probably get blasted for saying this but my primary tow vehicle was a 1995 Grand Voyager with a 3.3 V-6 external trans cooler, gas shocks, and 500 lbs over load springs in the rear. Do not get me wrong I love my 4runner but when it comes to the go juice, well we pretty much all know the 3.0 is not going to win any races. I was very suprised that the 4runner was so unhappy with the 3500 lbs boat and trailer at 55mph. Maybe I underestimated the van. Any how, long tows will be with the minivan until I get ahold of a v-8 4runner in the next year or so. So when you see me in my white minivan with runabout in tow don't laugh too loud cause on the next hill I'll be back to say hi. I guess the differance really surprised me.