View Full Version : installing a four pin trailer harness

06-08-2005, 04:13 PM

i'm one of those people who will never max out my towing capacity. i dont want it, dont need it, and there fore have no reason to spend 78 for the 7 pin plug just to spend another 23 for an adapter to make it the four pin i wanted in the first place.

so here is what i did to install an inexpensive 4 prong harness


Hoppy 4 wire flat vehicle end trailer harness PN 48035 available at autozone. 3.99

2 12v diodes, radio shack PN 276-563(required for dual wire park/brake lights) 1.29 for a package of 2

optional but recommended is wire loom, 1/2" conduct tite PN 85634 2 packs at 2.99 a peice.

4 prong harness holder that came with your mopar trailer hitch.

1 straw, heat shrink tubes or electrical tape and solder.

drilling is not required!!

1. remove tailights. you must pop the center portion of the pop rivets up from the sleeve on the inside lip of the lights, then remove them. next, pry up the two "speaker grill" looking panels in the cargo area. next reach inside making sure not to cut yourself, and feel around for the plastic nut. unscrew it and your tail light will slide out towards the rear of the car. unplug.

2. mount four prong plug in plate, and then mount that into the hitch using the four screws in the parts bag, and the predrilled holes.they arent tapped, so it'll be a struggle to start them. just make sure not to tighten them too much as your screw head will pop off(as can be seen on mine)

3. WIRE ROUTING:seperate the green right turn wire from the others and cover with wire loom. then take remaining three wires and cover with other loom. take these three wires, wrapp them around towards the right and the rear and they will fit snug up in the bottom lip of the bumper cover behind the pop rivets. this will completely hide them. then route them above the corner of the hitch to keep the wires snug, hidden and away from the tailpipe. do the same with the right hand side. next lower some string in the hole left by the missing tail light, tie it around the wire loom, and pull it back up thru. do this with both sides(note. depending on how agile you are with working with small bits of wire, you may need to tack on a bit more wire for free play)

now for the pinout. all wiring will be done to the main harness, so that you can still easily remove your tail lights if desired. therefore, all wires discussed are looking at the main harness plug.

if you look at the plug, there are five wires, 3 on the top row and two on the bottom. they should look like this.

1 2 3
4 5

1- park white w/ purple
2- ground black
3- turn signal white w/ dark green strip on left, and white with yellow stripe on right
4- brake- green w/white stripe
5- reverse

4. first wire in your turn signal and ground as they are no brainers. make sure and do the right side as well.

5. now is the only slightly in depth part. since the car has a seperate wire for park and brake, you cant just wire them both up, or both filiments will light up continuously. so now is the time to install the diodes. since i get the core diode with hard metal ends, i first make a cap for it. my personal choice is to take a peice of your average straw and shrink tubing. the straw is stiff, slightly flexible, and plastic, while the shrink wrap will help weather proof and makes it slightly more impact resistant. tape the ends and viola, bulletproof. connect one of these on the park wire, and one on the brake wire(make sure they are facing the right way!!!) finally connect both to the park wire. tape, tube and seal all ends as appropriate, and reconnect everything.

you now have a totally hidden 4 prond wiring harness that required no drilling, minimal splicing, and costs about 15 for all the parts and odds and ends.