Boat Trailer Wiring to Highlander ?

[SPAD7]

I purchased a new 2010 Highlander base model with the tow package. I had the dealer install the hitch and wiring.

Today for the first time I hooked up my trailer to check out the lights, I have an electrical short in the car coming from the wiring harness area near the brake pedal smoke and all.

I suspect I did not wire the trailer correctly. Here is what I have.

• A 4 way plug

• white, yellow, brown, and green coming out of the car.

• white, yellow, brown and green coming out of the plug on the trailer.

• Going into the trailer plug from the trailer is white, yellow, green and yellow/brown and green/brown.

I connected the yellow/brown and the green/brown to the brown wire going into the plug.

My right side turnsignal worked, left side did not.

Thanks for your help

Mike Sarasota Fl

[newsrv]

Hope this helps. On the Toyota (according to the wire harness instruction part PT219-48871)
Yellow is for the Left Stop/Turn light
Brown is for the Tail light
Green is for the Right Stop/Turn light
White is the Ground

This is also what etrailer.com shows for a 4 wire setup.

You could test the trailer wiring by connecting the White ground wire to a battery (- terminal) and then, one at a time, and connect the other wires to the battery (+ terminal) and see which lights are on.

Also make sure that the trailer's grounding is intact, sometimes the frame grounding is faulty due to rust or corrosion. This may cause an electric path thru another wire.

[SPAD7]

Newsrv; I tried the battery test and all of the lights are working as they should. So why the short in the car?

[Zembonez]

Originally Posted by SPAD7

I purchased a new 2010 Highlander base model with the tow package. I had the dealer install the hitch and wiring.

Today for the first time I hooked up my trailer to check out the lights, I have an electrical short in the car coming from the wiring harness area near the brake pedal smoke and all.

I suspect I did not wire the trailer correctly. Here is what I have.

• A 4 way plug

• white, yellow, brown, and green coming out of the car.

• white, yellow, brown and green coming out of the plug on the trailer.

• Going into the trailer plug from the trailer is white, yellow, green and yellow/brown and green/brown.

I connected the yellow/brown and the green/brown to the brown wire going into the plug.

My right side turnsignal worked, left side did not.

Thanks for your help

Mike Sarasota Fl

I'd look here. It doesn't sound like the problem is with the car.

[newsrv]

Interesting. If it were me I would verify that the Highlander is okay. I would either use a VOM or a test light to verify that each of the 3 (plus ground) Highlander plug connectors work properly.

When you did the test on the trailer lights, did you separately test the yellow/brown and green/brown wires? If so, what light(s) did each wire turn on? And did the other wires turn on the respective lights as given in my first post?

[SPAD7]

I took the Highlander in to Toyota, the converter box was fried and they replaced it for me.

I went to U-haul and bought a trailer plug that has the 5 wires on it going to a 4 way plug, there are 2 brown wires on the plug, I hooked up y - y, g-g yb-b and gb-b.

I checked the lights by using the 12 v battery, and here is what I got ????

green wire only, lights up trailer on right side facing the car.

yellow wire only lights up both sides of the trailer ?

yb lights up all running lights both sides of trailer

gb same.

As I understand it this is not correct, the yb and gb should have only lit up only one side

the yellow only should have lit the left side of the trailer.

I did not plug it into the car.

Confusing, next step is to take it to a trailer place.

Mike

[Zembonez]

Nice of Toyota to replace the box since it doesn't look like it was their fault but the fault of the trailer wiring that killed it!

Cool!

[SPAD7]

Final update on my trailer wiring problems, yes the trailer side was the culprit, there were several wires with broken insulation and bare wires exposed up inside the trailer crossbars.

But I also noticed that the tow package on the Highlander came with a 30 Amp fuse ! Should have been a 10 amp fuse which would have blown before frying the tow harness.

I replaced the 30 with the recommended 10 and the fuse did blow once before I got the trailer wiring replaced.

Everthing works now, the trailer lights even flash when I lock the car with the remote. Cool

Thanks for all the advise. Mike