Honda Fit (GK) Bi-Xenon Projector Headlight Retrofit

Collect both projectors, shrouds, the HID kit, relay harness, paint, and adhesive before starting. Because the housings are sealed with heat and the paint needs to cure, this is not a job to rush between errands; set aside two to three days. If the Fit is your only vehicle, arrange alternate transport so you are not forced to reassemble a half-aligned headlight in a hurry.

Take the front bumper off to reach the headlights. Remove the two screws at each wheel-arch side and the two screws along the bottom edge, then release the four clips underneath the bumper and the five or six clips across the top of the grille. With the fasteners out, the cover pulls forward and off. The layout is straightforward once the clips are located.

Each headlight is held by four screws and a single clip, all easy to spot once the bumper is clear. Remove them and lift the assembly out of the car so it can be worked on at the bench.

Soften the butyl sealant by placing the headlight in an oven at 250 F for about 10 minutes. There are four screws around the perimeter of the lens; back them out. While the sealant is still warm, grip the assembly at the apex and pull the clear lens away from the housing. Being firm here is fine; work steadily so the lens releases without cracking.

The chrome reflector shield has to come out to make room for the projector, and it cannot be left in place. A retaining clip makes it awkward to simply unclip, so use a rotary tool to cut the glare shield free. Trim only as much as needed to seat the projector and clear the beam path.

Give the projector shrouds and the inside of the headlight bowl a matte black finish with VHT spray paint. Lay down adhesion promoter first so the paint bonds and does not flake. A heat gun or the oven speeds drying between coats.

Fit the projector through the reflector opening and secure it with its retaining nut. Wrap the threads with Teflon tape or add grease so the nut does not bind and strip, which was the failure that produced a crooked beam on the first attempt. Rather than super glue, bond the adapter with a JB Weld KwikWeld steel stick: it gives roughly 6 to 15 minutes of working time to align the projector before it sets, then about an hour to fully cure. Align each projector with both lights powered so the pair matches rather than sitting at odd angles.

Run the H1 HID ballast and igniter for each projector. A relay harness is required to interface with the factory plug; do not try to feed the kit directly off the stock connector. Because the Fit uses a dual-filament bulb for low and high beam, use an H4 motorelay harness so the solenoid and both beam functions are driven correctly. Secure a clean chassis ground for each side, and choose ballast mounting spots that stay clear of heat and moisture. If you are also converting the fog lights, mount those ballasts in the same session.

Return the assembled housing to the oven at 250 F for about 15 minutes to remelt the sealant, then set the lens back on and drive the perimeter screws home. Warm it once more at 250 F, giving it 15 minutes, then press firmly all the way around the seam, and confirm every screw is tight so the housing stays watertight. Reinstall the headlight with its four screws and clip, then refit the bumper.

Park facing a wall at roughly 25 feet with both headlights on so you can see where each projector points and match them to each other. Perform the aiming check on low beam. Adjust until the cutoff sits level and the two beams are even before the adhesive has fully hardened.