View Full Version : wiring connections 7 to 4

09-12-2006, 03:05 PM
I'm hoping to drive (far) to tow home a used 1987 model 23 in a couple of weeks and I'm trying to get ready. The TM has a round 7-pin connector and my tow vehicle currently has a 4-wire flat connector. Do I have to get my vehicle rewired? What are the other 3 wires for? Do any of them have to do with the brakes? Is there an adaptor that would make all the necessary lights work?

Thanks in advance.

Tuscany Bandit
09-12-2006, 03:16 PM
Try this:

09-12-2006, 03:22 PM
There's a diagram of the 7-pin Bargman at the end of this link:
You will see that the extra wires are for 12V power, 12V auxilliary power and the TM electric brakes. You don't need to replace the wiring that already exists for the lighting, just get the new wiring added. It might be easier just to cut the four wire connector off and wire to a new Bargman connector, than to try to adapt.

You said you'll be towing a long way. You'll need a brake controller installed in your vehicle and maybe a WDH depending on your tow vehicle.


09-12-2006, 04:31 PM
When I said "long" I meant 260 miles.
Problem is that I don't want to invest in all the adaptations to the TV until I'm sure that I'm going to buy the trailer, which I haven't seen yet.
I'm thinking that I could get it home and then add the brake controller and the WDH if needed. Am I looking for trouble?


09-12-2006, 05:57 PM
When I said "long" I meant 260 miles. I'm thinking that I could get it home and then add the brake controller and the WDH if needed. Am I looking for trouble?Oh, yes, you are looking for lots of serious trouble! You CANNOT / MUST NOT tow with a normal tow vehicle if you do not have brakes in the trailer, and you can't power up the brakes in the 4-pin connector. Do something else - ANYTHING else! Rent an RV with a 7-pin connector and a brake controller. Rent a big heavy U-Haul truck with a trailer hitch at the right height (about 18" off the pavement is pretty close for a temporary setup), even if it doesn't have a 7-pin connector. Borrow your buddy's tow vehicle. Take an ox-yoke over your neck. But DON'T tow without brakes behind a normal tow vehicle!

The WDH can wait, though you WILL need one. You will not need sway control. But brakes cannot wait. Among MANY other considerations, if you are involved in an accident, and you don't have brakes, you WILL be held liable.


09-12-2006, 08:02 PM
I have to agree with Bill on this issue, the liability would be all yours should you get into an accident.

I'd think that it would be worth an extra trip to look at it, and then go back with the proper 7-pin connector and brake controller.

If you're looking to buy a trailer, you're going to have to end up with the 7-pin connecter and the brake controller anyway?

We put ours on, and then went looking for the trailer. It wasn't that expensive.

Bill & Lisa
09-13-2006, 09:38 AM
Just to add my voice.....if you are getting ANY trailer large enough to have their own brakes (basically anything bigger than a pop up) you will need the bargman plug and controller so might as well get them now.


09-13-2006, 09:46 AM
We faced a similar dilemma purchasing our used TM. It was for sale by a private party in Wilmington, NC. I ended up borrowing my niece's 2000 Tundra (manual transmission) and had a brake controller (7-pin wiring) installed. I knew it would be safer to have the brake controller and didn't mind paying for the unit and the installation. She now has a brake controller for future use . . . and I have access to her Tundra should the need arise.