Adding 7 wire wiring to 4 wire van

[gksmith]

I want to occasionally pull my pop-up trailer having 7-wire wiring with my 2002 Dodge 3500 Leisure Travel Freedom 4 camper van that has 4-wire wiring. I took the van to my local RV dealer (who does not sell motorhomes) and he could not find an easy way of running a new wiring harness to the rear due to extensive expandable foam undercoating. So he declined to do the job.

I have considered adding an adapter that enables me to connect the trailer to the existing 4-wire cabling of the van, leaving the other 3 wires disconnected. Of course I would not have brakes on the trailer then. The trailer weight is right on the border line of the requirement for electric trailer brakes in Nebraska. So I am tempted to do this.

I would appreciate comments and/or suggestions!

Gregg

[hepcat]

Go find an auto-electric shop. They'll find a way to run the wiring for you. It's what they do. Don't tow without brakes if you have them on the trailer. If you don't have them, you can't be negligent for not using them... if you DO have them, on the other hand... regardless of the weight requirement to have them, you're negligent if you don't have them hooked up.

[Ron J. Moore]

Gregg, check out a U-Hhaul Place. I have a 7-4 that plug in and it works either way..no meds required. Ron

[hepcat]

Originally Posted by Ron J. Moore

Gregg, check out a U-Hhaul Place. I have a 7-4 that plug in and it works either way..no meds required. Ron

The 7-pin to 4 pin converter is no problem... all four pins are already hot in the Bargman connector. Going the OTHER way though... the wiring to three of the pins; charge, brakes, and backlights, is missing.

[markopolo]

For some ideas: I routed the 10 gauge (30A) power wire in plastic loom through the van frame rail. It provided an easy path front to rear. I taped up and fished the loom through first. It would be easy to beef up the ground at the rear. A wireless brake controller like the Prodigy RF eliminates the need for the brake control wire. The backup light wire is unused / not needed on my setup - probably not used in most setups.

I probably have done 5000 miles towing using the wireless Prodigy RF since I installed it and it has been problem free.

[gksmith]

I investigated your Prodigy RF controller some more. I was astonished at first with the price. But when comparing its extra cost to the probable labor cost of a conventional installation, plus the convenience of being able to easily switch tow vehicles, the cost seemed more reasonable.

But, to clarify, the only wire needed is the power wire? Instead of running the power wire all the way to the front, could I not run it only to my power converter, which is located at the rear of the van? This would eliminate running any wire to the front of the van. Correct?

[markopolo]

Yes it is expensive but my model year van didn't have the factory brake control module sockets so it would have meant splicing in a wired brake controller. Like you, I figured the dollars saved on labor using the DIY wireless unit would probably equal it all out.

The 4 way to 7 way adapter I used had a plug to insert the 4 way connector that was already on the van. I taped off two wires - the brake wire and the backup light/surge brake wire. I used the two other wires - the 12V+ power wire and the 12V- ground. I put a 30A circuit breaker on the 12V+.

Curt-d_57102_a__53491.1405454134.1280.1280-500x500.jpg

The 4 way to 7 way adapter I used had a backup beeper but I disabled it.

some info: http://www.classbforum.com/forums/f8/wiring-for-trailer-3979.html
Originally I installed the connectors for a cargo box and other accessories but have since been towing a travel trailer with the van.

I don't see any reason to not make the 12V+ connection where the house battery connects to the converter as long as that power source can't be disabled or interrupted by a battery disconnect switch etc.

The Prodigy RF main unit mounts to the trailer frame and the wireless unit plugs into a 12V accessory outlet on the van dash.