Hey all,

I recently picked up a small Hualmark enclosed cargo trailer.Its an 8'x5', I got it for $850 buks so it needs a little TLC. I am going to replace the 4 pin wiring harness with a fresh unit.

Should I account for any fuse replacement or anything else besides straight forward wiring up my lights? I couldnt find any fuses etc. when I checked. The wiring harness is pretty hacked up so I have no idea whats been done with to it over the years. it has 4 marker lights on the roof, an interior light and brake/signal lamps thats it. Im figuring its just a matter of making my connections to lamps and thats it correct? Any tips or advise is welcome.




Thanks in Advance! Jake

 

with the regular flat 4 plug just run you wire and plug it in. no fuse to worry about as long as your truck has the harness if not it is just a junction that will plug into your wiring under you rearend. just make sure that when you pull your new wire you connect it to the old with tape and pull out the old which will runn your new. only telling you because i have messed up before. and had to fish it down the tubing. Not fun with out a fish tape.

 

as far as figuring out which lights on the plug go to what. look at your 7pin connector on the bumper, the cover has the schematic molded to it.

 

and it is correct unlike my old ford. glad its gone!!!!!

 

Thanks for the help guys

Very helpful information from the both of you! Sounds like this should be a straight forward job.

 

If your Dodge has a tow package, it may also have a dedicated fuse for the tow circuit - mine does.

Four wires usually mean:
Left stop & turn
Right stop and turn
Running lights
Ground.

I have found the ground is often white, the running is often brown, and the yellow and green are the left and right (not sure which color is which side).

Your turn signal and stop signal on each side, as it is only one filament of the two filament bulb, is the same wire. In other words, there is not an individual wire just for brake lights.

Make certain that the ground connections on the trailer lights are tight - they often loosen up and get corrosion.

Most connections are wired straightforward and as indicated. It is easy with a simple test light to check same, in the event they are not. If you only have a 7 pin, there are adapters available at every auto parts store which plug into the 7 pin and present a 4 flat for connection to the trailer.

 

You will need to run a separate wire for a 12v feed for the interior light.

 

4 wire
Yellow / left, stop
Green / right, stop
Brown/ Black is clearance / marker
White / ground

7 wire
Black / 12v marker
Brown / 12v marker
Yellow / left, stop
Green / right, stop
Blue / Brake
White / ground
Red / Aux

On equipment trailers and larger trucks
7 Wire

Black / Power
Brown / power
Blue / Power beyond ( trailer hot line )
Red / stop
Yellow / left
Green / Right
White / Ground

 

My Interstate utility has the interior light tied into the running lights...much simpler that way...can still use the 4-way flat.

Marc