I know there are lots of posts on the 4 Hi mod for the earlier models but they’ve gotten pretty lengthy and confusing so I thought I’d post up how I just did mine. Hopefully this will make sense and put everything together in one post. I’ve drawn from the other posts as well as from some questions I’ve had answered, so thanks to everyone who has contributed on the other threads.
From Jkmotorsports: Pre-03 models
Behind the driver's side headlamp assembly, locate the harnesses to the low and high beam bulbs. The low beam should have a yellow and an orange wire. The high beam should have a purple and an orange wire. When buying the relay, JKMotorsports says “Ask for a typical SPDT automotive relay, such as those used in some aftermarket driving/fog light systems. These will have 5 contacts labeled 85, 86, 87, 87a, and 30. You might have better luck going to your local stereo/alarm shop, as these are always used , especially in alarm installations. They'll know exactly which one to give you; the type used in aftermarket automotive integration are basically industry standard.”
I have no idea how much it cost. A friend who installs car stereos and theft deterrent systems gave me one.
The first pic shows the basic materials I used. Relay, wire, shrink tubing, insulated crimp female connectors for the relay, dielectric grease, and I forgot to include the uninsulated crimp wire connectors.
First I crimped 18” of wire to the female connectors, using some dielectric grease on the wires. To help keep out moisture I then put some shrink tubing around where the wire enters the connector. It wouldn’t shrink tight so I used a smaller size over the larger. Getting it over the larger was a pain. I didn’t have wire colored to match the lights so I used different color shrink tubing on each to help identify them. The second picture shows this.
First, I wired the relay following the third picture (thanks FergHoe) and you only need to perform this on one side of the vehicle (thanks JK).
I did this with wire taps to make sure I had it right before making it permanent, see picture 4. To help keep it dry, I kept the relay in the engine compartment and threaded the wires through a gap to get to the headlight compartment.
Once I knew things worked like they should, I removed the wire taps and cut the headlight wires where the tap had nicked them. I used dielectric grease on every crimp connection. I then stripped enough headlight wire to insert into the uninsulated crimp connector. I fanned the headlight wires out so I could intertwine them before twisting them together, hopefully giving a better, stronger connection, see picture 5. Crimp the twisted headlight wires in one end of a crimp connector.
I can only put 5 pics on one post so I’ll finish up in the next post.
