Does anyone know the proper way to convert my 4pin trailer harness to 7pin and still get all the functions of the 7pin. Im going to be towing a tent trailer that needs to be charged with my 2002 tacoma while its being towed. I just purchased a 4pin to 7pin harness adapter for my tacoma. On the truck side its got the usual 4 pin that connects to my trucks 4pin and it also has 4 additional wires. (Yellow) auxiliary, (black) power supply, (blue) electrical brakes and (white) ground. On the trailer end it comes out with the necessary round 7pin plug. My question is, what is the best way to get power to the black wire on the harness adapter labeled power supply? Do i run a 10 gauge from my trucks battery all the way to the harness or does it need to go from the starter with a relay of some sort and a switch? If anyone has ever done this please help me out! Thanks so much.

 

anyone?

 

google 4 pin to 7 pin. basically you do run the missing wires.

 

You need to run wire (at least #10) from the battery to the Bargman with a 30A fuse and a relay or isolator so that the car battery does not drain empty with the car off. If you don't use large enough wire or a good enough connection you will have a voltage drop. In other words the battery won't charge and/or your fridge will drain the trailer battery if you run on 12V.

Likely you need a brake signal from your controller too. Get a Tekonsha controller such as the Prodigy. Don't settle on a cheap controller.

The other connections can be obtained by tapping into the 4 pin. The exception being the reverse lights which are optional but available at the rear of the vehicle.

 

Lars Dennert this is the exact answer i was looking for!!! Thank you so very much for the info!

So let me get this straight....... from the positive side of my tacomas battery i need to run a 10 gauge wire and hook up a battery isolater as close to the trucks battery as possible? Then from the isolater continue running the wire to the rear of the truck and hook it up to the 7pin round? Does the location of the 30amp fuse matter? Close to the battery or should i put it under my truck near the 7pin round? BTW thank you so much for your help because ive been asking around for a couple days now and no one knows how to properly hook this up!!

 

put the fuse near the battery to protect the wire and battery in case of a short. Since you are going through the trouble, run a brake lead at the same time. #12 is fine. I used #8 for power btw.

Here are a couple of tips too. When storing the trailer charge the battery using shore power and then pull the fuse at the trailer battery for storage. Don't charge batteries for long periods (weeks) unless you have a three stage charger or you will boil off the water and cook the battery.

Have fun camping.

 

Ok. So both the isolator and 30 amp fuse should be located in the engine compartment of my truck? Then run 8 gauge all the way to the connector? Sounds easy. Now I gotta look for a good isolator. Thanks!!

 

Yes. You can also use a 30 or 40 amp relay that gets switched on with the ignition if you can't find a battery isolator. Most stereo stores will have something to control power to aux amps.

http://www.northerntool.com/webapp/w...2955_200342955