Wiring trailer connector

2003 Highlander here.

I have a Hopkins wiring harness for a trailer which requires a separate lead to the positive side of the battery.

I know I can route beneath the vehicle, but would there be a channel within the frame through which the wire could be fished? This may protect it a bit from road salt and the elements.

Reply to
franz fripplfrappl
Loading thread data ...

Easy answer: Follow where Toyota routed the tail light wire bundle. Unless they've changed things a lot over the years, that bundle should be totally internal, except for the end where it enters the tail lights. When you reach the front, you'll have to carefully snake your wire out at the edge of one of the bundles that goes to the engine compartment. Plan this VERY carefully to avoid heat sources, and places where it could get in the way of things the mechanic needs to work on. In other words, continue to follow what Toyota did.

Reply to
JoeSpareBedroom

Thanks.

I have fished the wire just inside the plastic molding on the driver's side of vehicle. Easy enough to do. I am now at firewall trying to figure best way to route wire through it.

I see there is a bundle of wires going through the firewall just above the steering column. These penetrate a rubber gasket. Very tight fit. Not sure I can squeeze much else through.

Have thought of puncturing the gasket enough so my wire goes through it.

Is this the only pass through the firewall?

Reply to
franz fripplfrappl

I would try to VERY CAREFULLY punch through the edge of that gasket with an awl. Then, tape your wire to that awl and slip it through.

Without being under your dashboard, I can't tell you if that's the only way through. I've worked on lots of Toyotas, but never a Highlander. Looking at the firewall from the engine compartment, do you see any other bundles coming through?

Another option is to make your own hole, but obviously, you'd be working in tight quarters with a drill. The trick to doing it right is to have a rubber grommet which fits the hole correctly. Otherwise, your wire will be rubbing against the sharp edge left by the drill bit. Car stereo stores often have a supply of these grommets. But, I'd still prefer to use an existing route. Whichever way you go, be sure to put a dab of silicone sealer around the wire.

Reply to
JoeSpareBedroom

Good ideas. Thanks. I think there's space to punch through existing grommet. Issue is on the engine side the space is so tight that it is difficult to squeeze my hand between things. Time to get clever, I suspect.

Reply to
franz fripplfrappl

It's a Hopkins wiring kit specific for the Highlander. There is an isolation circuit to protect car in the event of a short on the trailer wiring. The circuit protector provides for a separate positive lead to the battery. There is an inline fuse on this wire.

Reply to
franz fripplfrappl

I have fished the wire along the carpet/molding on the driver's side for a very easy and protected install. Issue now is getting wire safely through firewall.

Reply to
franz fripplfrappl

Got any house-type wire handy? Pull one strand out of the bundle and use that as a snake. It's stiff enough that's it's easy to "steer". The white conductor's easiest to see among all the dark stuff in the engine compartment.

Reply to
JoeSpareBedroom

Is that inline fuse going to end up in the engine compartment? If so, does it appear to be made for moist environments? If not, consider going to to an auto supply place to see if you can find a waterproof fuse holder. Better yet, a boat store/marina. If you can't find one, at least route the wire so any moisture which collects doesn't drain toward the fuse holder.

Reply to
JoeSpareBedroom

Go through the inside. Bit more work, but much better protected. Use 12-3 or 10-3 SJO jacketed extension cord, and it's already in a protective outer sleeve. There is usually a wiring notch either inside the door sill plate, or just inboard of it under the carpeting.

Use one wire for the trailer light feed and you have two extra leads from the battery to the rear of the car. For a rear lighter socket/ power outlet for your 12V air compressor, or a separately switched set of backup/work lights, or a modest subwoofer amplifier, or...

-->--

Reply to
Bruce L. Bergman

The coat hanger will gouge the crap out of whatever wire it scrapes. Maybe. He won't know, really, because the damage can't be seen. The edge is the only way to go, and the awl is better because it's point is tiny compared to the cut edge of a coat hanger.

Reply to
JoeSpareBedroom

It has a moisture proof case.

Reply to
franz fripplfrappl

Thanks.

Vehicle already has 12v receptacle in back.

Reply to
franz fripplfrappl

Classy :-)

Reply to
JoeSpareBedroom

For the record in case others might need to know...

I fished the single lead along the floor and beneath the molding on the driver side of vehicle. From rear to front, this took 5-10 minutes.

To go through firewall, I located a bundle of wires passing through a rubber grommet/gasket just above steering column. From the engine compartment and using a coat hanger, I carefully poked the gasket membrane and pushed a few inches of the coat hanger through careful, of course, NOT to hit or damage any of the other wires.

Then I taped a piece of string to the coat hanger and pulled the coat hanger back out of the hole so I ended up with string on both sides of the grommet/gasket. I then taped the single lead to the string and pulled until the wire was in the engine compartment. It helps to overlap the wire/string by 2" or so.

Then it was only a matter of using wire ties to fasten the wire and make things look clean. Attached the inline fuse to the wire and then the other side of the fuse to the positive post of the battery.

A very simple process. In all, probably took 45 minutes, 30 of which were spent figuring things out.

In all, a nice clean install.

Reply to
franz fripplfrappl

If it's not too late, it's generally better to push the wire down under the carpet, and not have it under the molding. No chance of foot pressure affecting the wire. Other than that, it sounds like you're ready to be a world-famous car accessory installer.

Reply to
JoeSpareBedroom

Thanks for the idea. Foot pressure shouldn't be a problem. Not enough give in the molding and I did put the wire beyond the lip of the molding, so it runs along side whatever wires are already there.

Not ready to be an installer, but I do admit it is fun to figure out puzzles. Now to find an appropriate trailer to pull.

Reply to
franz fripplfrappl

Two things: If your car is an automatic you MUST have an auxiliary transmission cooler installed in front of the radiator, this is not optional. Towing heavy things can cook the tranny real fast.

And if you are at the upper end of the weight limits for your car, order a trailer with brakes. All styles can easily made with them, but you may have to special order it. The builder just has to have (or order in) an axle with brake hardware when they start assembly.

You can add brakes on some already built trailers if they have the brake backing plate mounting flanges on the axles, but it costs more to order the brakes as parts than as a complete axle with brakes. (No flanges, you have to replace the axle.) And the trailer builders get the complete axles for a lot less than you will, since they order them a dozen or two at a time...

-->--

Reply to
Bruce L. Bergman

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.