I was just wondering what type of headlight harnesses are out there and what experiences people have had. Also, has anyone had any success in just using the stock harness (at least until a heavy-duty one ships in). Is there a difference for the 1999 headlights than different years?

 

Oh yeah, another thing. Does anybody know whether or not the 1999's have a ground switched system?*Ground switched systems require a special harness

IF YOU ARE NOT SURE IF YOUR VEHICLE IS GROUND SWITCHED OR NOT DO NOT E-MAIL US AND ASK WHAT SYSTEM YOU HAVE. We do not have a list of which vehicles are ground switched and which are not. This information does not exist in the industry.

YOU MUST PERFORM THE FOLLOWING TEST BEFORE ORDERING A HARNESS. ATTEMPTING TO ATTACH A REGULAR HARNESS TO A GROUND SIDE SWITCHED VEHICLE OR THE OTHER WAY AROUND CAN CAUSE DAMAGE!

PROCEDURE FOR TESTING FOR GROUND SIDE SWITCHING

Head Lamp Configuration A: THREE WIRES FOR HIGH BEAM AND LOW BEAM WITH ONE WIRE BEING COMMON (such as H4 and 9004 systems):

1. Disconnect your original harness from your head lamp or head lamp bulb. Use an automotive test light clipped to ground to check if each of the three wires is a ground or a hot.

2. Have a helper sit in the driver seat and switch the headlights from low to high while you move the test light probe from terminal to terminal on the harness plug.

3. You should find that one of the wires either stays constantly grounded or is constantly hot (this wire will always be the same whether low or high beams are on).

4. If ANY wire is constantly hot, you have a ground side switched system AND WILL REQUIRE A SPECIAL "GROUND SWITCHED" STYLE HARNESS. If the wire is constantly grounded, a regular harness will work.