Why Would Trailer Wiring Harness in 2008 Toyota Highlander Stop Working

Question:

I have a 2008 Toyota Highlander Hybrid. It has an existing wiring harness that was installed by a hitch specialist a couple of years back 118449 T-Connector + Installation. The wiring is no longer working. I just looked and it appears to be a straight quick connect spliced into the back wiring system with no additional converter module that I can see. The uhaul guy said there was nothing connected to the battery in front. * Does this mean that I have a factory tow package with a converter mounted under the dash? * How would I confirm this? * If its electrically dead when tested at the back flat connector - does this mean that its just a blown fuse? Could the power module be fried? * What would I order from you guys, since I dont trust the Pros that Ive spoken to here, I got a quote for $245 to replace...I have uhaul saying it just needs a new quick connect....and I have someone saying Whatever you do - dont do a quick connect, since you have a Hybrid, without a power module you could fry your electrical system instead of just the box??? Help! Thanks,

asked by: Andy B

Helpful Expert Reply:

If you had the part # 118449 installed in your 2008 Toyota Highlander that would indicate that you do not have the factory tow package. This harness comes with a converter box built into it so I am not sure how you would have actually had this harness installed if you don't have a converter box.

If instead what you have looks more like the part # 56042 then you do not have the # 118449 installed.

The part # 118449 has an inline fuse on it for the power wire that connects right the port for the harness. Check to make sure that is good and replace as necessary.

Sometimes shorts in trailer wring can cause the converter box to fail. This is actually the way they are designed. They basically sacrifice themselves so that your vehicle's wiring doesn't get damaged. How noble, right?

What you would want to do is first try to fix the short on your trailer's wiring and then replace the harness. Look for cut or exposed wire and fix as needed.