johnr265

What plug does the trailer have for wiring, a 4 or 7 pin connector? If the trailer has a 7 pin connector and your tow vehicle only has a 4 pin connector, will the electric brakes work properly if you use a simple converter? Thanks. Tow vehicle is getting wired this weekend and they want to put a 4 pin harness on and I want to make sure it will work properly with the trailer.

Crazy Canuck

If the trailer has electric brakes the Trailex comes with a 7 pin spade (flat pins) connector. It's the most common.

The four pins on a 4 flat trailer connector:
- Left Signal/Brake
- Right Signal/Brake
- Running Lights
- Ground

Electric brakes will not work on the trailer (if equipped) through a Flat 4. You can cheat it by making an adapter from the 4 on the vehicle to 7 on the trailer but the brakes won't work.

An electronic brake controller is required. Tekonsha came out with a portable RF system that actually works pretty well. If you have the choice though get your controller installed permanently and don't buy the cheap controllers. They're junk. Last year my company sold almost 300 brake controllers. Most were the Tekonsha Prodigy. We never have problems with them.

Tom N

You want the 7 pin connector to use electric brakes. I second the Tekonsha Prodigy controller. If you plan on towing a utility trailer as well, there are wiring harnesses for the tow vehicle that have both a flat 4 and round 7 pin plug (newer Land Rover, for example).

johnr265

Thanks for the input. It's strange. Uhaul is installing this on a Jeep Grand Cherokee Diesel and they installed the prodigy brake controller as well. He is in the process of installing the four pronged harness though and he assured me that it was fine. He was having problems connecting the harness as there is no pre-wire in my car (non-tow package) so he is going to finish it up tomorrow. I guess I should insist on the 7 pin flat connector. Sounds like the brake controller would effectively not even work the way he was trying to set it up!

Tom N

I would assume the Trailex will come with a 7 pin ROUND harness, as has every electric brake trailer I have seen. I have never seen a 7 pin flat, but I could be wrong. You need the 7 pin design to charge the battery on the trailer which is for emergency braking if the trailer should come unhitched.

KOAN

Both of my Trailex trailers (open and enclosed) had surge brakes and a flat 4 pin connector. Trailex does make trailers with both types of brakes, though, so you should find out what you will have.

johnr265

Oops, I meant 7 pin spade (flat pins as opposed to round pins) but of course, still a round plug.

TurboCup87

AFAIK UHaul doesn't use anything with electric brakes, so they are only used to the 4 wire systems. If your trailer is going to use electric brakes, you need the proper wiring for the so called RV 6 or 7 wire system. This includes a wire to your brake controller near dashboard. You need a signal from the brake light as well. Agree that the Prodigy is an excellent brake controller.

BTW, nice color choice on your car!

Crazy Canuck

It's a round connector with flat pins. A round connector with round pins is also available but not common.

Tom N

Good point. The question is surge vs. electric brakes. The surge do not require electrical input, hence 4 wires. The electric requires a controller, hence 7 wires. My 2008 Trailex EB (electric brake) came with the 7 wire harness with spade terminals, except the center.