Headlights

H-5 to H-4 Conversion

I swapped the Euro 8 inch H4 headlamps from my '79 Euro track car to my '93 US GTS. There are a few subtle things to watch out for. You must have the entire Euro/ROW 8 inch H4 lamp and frame. These headlamps consist of the glass lamp assembly and the frame that attaches to the headlamp "fork" that swings up from the fender. If you don't have the Euro/ROW headlamp frame, you cannot make a swap with the DOT lamp by just adding the Euro/ROW bulb section to a DOT frame. The DOT bulbs have the structure to attach the plastic headlamp case. The Euro/ROW frame is where the plastic headlamp case attaches. Is this a clever modification to make a H4 change more difficult or just a difference in design philosophy? Something for research to answer, I guess.

For those who have pre-S4 DOT lamps, I agree that the 8" lamps (without trim) look much nicer than the 7 in. lamps with trim. However, if you want the H4 lamp pattern use the Hella H4 replacements. You get the same lamp pattern and save about $120 per headlamp!! This article doesn't cover a 7 to 8 inch conversion. It only addresses the 8 inch DOT to Euro/H4 conversion.

a. US 8 inch H5 Headlamp Removal

The US headlamp has four Philips head screws that hold it to the frame. To remove the headlamp:

a1. Raise the headlamps. In my 93 GTS, the headlamps lower when the ignition is turned off followed by the headlamp/parking lamp switch being turned off. Therefore, I kept the parking lamps on during this procedure. (In my '79 and '83 the headlamps remain raised if the headlamps are turned on, the ignition is turned off and then the headlamp switch is then turned to the off position.)

a2. Remove the three screws that hold the plastic headlamp case from the headlamp assembly.

a3. Unplug the headlight electrical socket from the bulb.

a4. Remove these four screws, but be sure to hold on to the headlamp unit because there is one more very important item to remove.

a5. At the bottom of the headlamp, is a "ball joint" fitting that continues to hold the assembly into the frame. This "appendage" appears to be what is left of the ROW headlamp leveling system. In the US models it is just spring loaded. Tilt the top of the headlamp forward just enough to gain access to the ball joint cover at the bottom. Use a flat blade screwdriver to gently push the black ball joint cover towards the rear of the car.

a6. The white ball joint socket (on the headlamp frame) has a few slits that run at a 90 degree angle to the headlamp frame. Use a flat blade screwdriver to gently pry the socket open a bit and pull the headlamp assembly away from the ball joint.

a7. Remove the headlamp assembly.

b. Removal of the ROW/Euro 8 inch H4 Headlamp

The ROW/Euro headlamps have a frame made to pivot up and down for "real time" headlamp adjustment. There are only two bolts that old it into place.

b1. Raise the headlamps

b2. Remove the three screws that hold the plastic headlamp case from the headlamp assembly.

b3. Unplug the headlight electrical socket from the bulb.

b4. The Euro assembly has two 8 mm nuts on each side of the headlamp. Remove these two nuts. but be sure to hold on to the headlamp unit because there is one more very important item to remove.

b5. At the bottom of the headlamp, is a "ball joint" fitting that continues to hold the assembly into the frame. This "appendage" appears to be what is left of the ROW headlamp leveling system. In the US models it is just spring loaded. Tilt the top of the headlamp forward just enough to gain access to the ball joint cover at the bottom. Use a flat blade screwdriver to gently push the black ball joint cover towards the rear of the car.

b6. The white ball joint socket (on the headlamp frame) has a few slits that run at a 90 degree angle to the headlamp frame. Use a flat blade screwdriver to gently pry the socket open a bit and pull the headlamp assembly away from the ball joint.

b7. Remove the headlamp assembly.

b8. Since my '79 Euro headlamp donor doesn't need headlamps, I cut off the H4 electrical socket leaving about 1 1/2 inches of wire to the socket. I used it for connection to my '93 GTS (see item d.)

c. Installation of the Euro/ROW Headlamp assembly on the previously DOT target car.

c1. Note the "up" side of the headlamp assembly.

c2. Line up the ball joint with the socket on the headlamp assembly. Gently push the ball into the socket.

c3. Use two flat blade screwdrivers to line the black ball joint cap with the white socket and push it into place. It is just a little snap, don't push too hard.

c4. The US frame accepts the Euro assembly two nut fitting. Push the bolt portion through the frame and attach the nuts.

d. If your US car has H5 bulbs, the electrical socket does not fit H4 bulbs. My solution was to leave the H5 socket (so if I need to go back to DOT lamps I can) and attach the H4 electrical socket as follows.

d1. Wire code: brown (31) is ground, white-black stripe is (56a) are the bright headlamps, and yellow (56b) is for the normal driving headlamps. The H4 lamp has three blades, looking from the rear to the front of the car, the top horizontal blade (parallel to the ground) is 56b/yellow/normal driving lamps; the left vertical blade (90 degrees to the ground) is 31/brown/ground, and the right vertical blade 56a/white-black stripe is bright headlamps.

d2. Trim back the plastic sheath that covers the headlamp wires by about 1 inch.

d3. Strip away about 1/4 inch of insulation about 1/2 inch below the H5 socket.

d4. Strip off about 1/2 inch of insulation from each end of the donor H4 socket wires.

d5. Coil the H4 socket wires around the target car's headlamp wires. Be sure you have the correct wiring for the socket.

d6. Test your wiring. Be sure none of the wires touch each other. Connect the H4 socket to the bulb. Turn on the headlamps, test for normal and bright lamps.

d7. Solder the wires together. [I prefer a mechanical solder connection to a pressure clip-through T connector. No damage is done to the original wire and the solder connection should be much less vulnerable to corrosion.]

d8. Wrap the exposed portions of the wire with electrical tape. I taped the unused H5 socket on-top of the H4 socket so it doesn't rattle)

d9. Plug the H4 electrical connector into the socket. Test the connection. Turn on the headlamps, test for normal and bright lamps.

d10. Align your headlamps. Be very sure the adjustment is correct. The H4 lamp pattern has a "knifelike" cut-off for normal driving lamps, vs. the "blurry diffused" DOT pattern. If the lamps are too high, or aimed to the left then you'll blind oncoming drivers.

Rich
'93 GTS "Euro Focused"
'83S (7 inch. "Euro Focused")
'79 Euro track beast, a few lbs. lighter and not a night racer!