Euro Light Installation

As listers may know, I finally installed my H4 Euro headlamps into my 1987 4kcsq. Not tough, but boy, did it take time.

Parts used for my installation:

• (2) Euro lamps
• (2) H4 bulbs
• (3) Three 30A SPST or SPDT relays (Bosch or Hella)
• (3) 30A in-line spade-type automotive fuse holders
• 16' of 10ga insulated wire
• 16' of 12ga insulated wire
• Box of 0.250" yellow-jacket female quick-disconnects
• Box of 0.312" yellow-jacket female quick-disconnects (hard to find. Call AMP for "samples")
• Either box of > 0.250" ring terminals or one really big one that will accept three 10ga wires simultaneously
• Crimper
• 1m of shrink-wrap
• Several 0.250" hex-head sheet-metal screws
• Small cordless drill

Here are the steps I took to do the conversion. Not too tricky, just really time-consuming. Again, this is how I did it, your mileage may vary. Pictures may show up here someday if anyone asks for them. These instructions assume that you are working on an aero-nose 4k, which means 1985 or newer. If you have the quad-light setup, well, get the quad H4s.

DOT lamp removal

The lamps are held on by four screws, two on the top, two on the bottom. Removal of upper and lower trim is also necessary. Might as well yank out the center grille too, while we're here.

1. Remove upper and lower trim from both lamps.
   Upper trim is held on by metal clips that can be pried loose with a flat-head screwdriver. They then swing away from the grille and can be removed. The lower trim is held on by two screws at the fender side, right above the metal trim piece below the corner marker. Look closely, you'll find them. This trim piece unsnaps from the center grille and also swings out.
2. Remove upper and lower screws from both lamps.
   The lower screws, now that the trim has been removed can be seen. Get a long-ish phillips-head and go easy on the lower screws. As the EC article says, these can drop easily and you will never see them again as they end up in the lower radiator shroud (or whatever is left of it). Use a magnetized screwdriver if necessary. You have been warned.
3. Remove center grille.
   This is necessary, but makes things so much easier. There is a small phillips screw between the fins near the center, below the "rings". Remove the screw and pop off the two metal clips that keep the top on. Lift and remove.
4. Remove lights from body work.
   Sounds easier than it actually is. You will have to wiggle and jiggle them all about to slide them from the bodywork. Unscrew the parking lamp bulb to make it go a little easier. No tricks, just work 'em out, and try not to bust anything.
5. Disconnect harness from rear of lamp.

Congrats, step one is done. Now, find out if you can sell the DOT lamps or put them in a safe place so you have "backup" lamps. Not that you'd want to use 'em or even wrestle putting them back in, but hey, what else are you going to do with them?

Now, just make your wiring harness, wire it in, and put the new Euro lamps back in! Warning, they don't go in any easier :).

Wiring

Below is a quick wiring diagram (non-standard, excuse me) that I drew for my setup. The general layout was inspired by Huw Powell and his page devoted to his own H4 wiring.

LH, LL, RH, RL, are left-high, left-low, right-high, and right-low, respectively. The "Low" and "High" diamonds on the left of the image are the signals from the switch. More on that later.

Where do "Low" and "High" come from?

They come from the old connector that used to plug into the back of the DOT lights. Using a voltmeter, test the connections to find out which of the three wires is Ground, Low, and High. Should be simple.

When you know for certain, mark the wires or write down the color codes somewhere. I'd tell you here, but it's better if you do it yourself. Then, snip off the old connector. Whooppiee! Now you've done it!

Where do "Low" and "High" go?

If you are at all like me, you have no clue which of the three prongs on the back of the bulb are what. Two approaches: use a good ohm-meter to find the resistances. Lowest is High to Ground, highest is High to Low, and the middle is Low to Ground.

But since you are like me and have an el-cheapo brand "needle-style" multimeter, you won't ever see the 1-ohm reading. So, Phil Payne to the resuce:

                         Rear of bulb

                          +-------+
                      +      Low      +
                      | G           H |
                      | n           i |
                      | d           g |
                      +             h +
    

Where do I mount these relays?

Well, that's a good question. I put mine under the radiator shroud on the side of the driver's side headlamp. There is a metal bracing on one side of the lamp, and fender on the other. I drilled small pilot holes and screwed the relays down onto this bracing. Makes for a short wire run and good grounds. I'll post a picture someday. I also am planning on fabricating a small aluminum "cover" to protect the relays from the elements, as they are semi-exposed behind the very side of the center grille. We'll see.

If you choose to put them there as well, please make sure to get short sheetmetal screws. You don't want the end of the screw protruding so far as to poke your expensive new euro lamps. There is plenty of space there for three relays.

Another listmember mounted the relays onto the vertical plastic thing that is right next to the radiator, fender-side. This plastic seems sturdy enough and the location is more protected from the elements.

Yet another listmember mounted the relays in the glovebox. You see, there are many options here. Just find out where you want to put them and go at it! Just take into account all the wire runs and use split-loom tubing if you are going far.

Tips for wiring

• Disconnect the negative post of the battery. Do not work on electonics without doing this. Life-threatening amounts of current could be yours with just a slip of a finger.
• Start at the rear of the alternator for +12v. There is a 10mm hex nut that holds on a big fat wire that eventually goes to the battery's (+) terminal. That's where you want to use ring terminals crimped to your 10ga wire.
• You must fuse the power connection. Either before or after the relays, it really doesn't matter. You need about 30 amps for the lows, and 30 amps each for the highs. Use more relays if you want to be careful.
• Use at least 10ga wire from the alternator to the relays.
• Use at least 12ga wire from the relays to the lights.
• Crimp and solder all connections. No butt-splices, please. You will regret it. Liberal use of shrink-wrap, too.
• Zip-tie with nylon straps all loose wires. You are working near the lower radiator hose, alternator, alternator belts, and the radiator here, so any flapping wires could cause serious injury to the car down the road.
• Use split-loom tubing to help tidy up the wiring that goes from one side of the car, along the lower radiator hose, through the cardboard shroud, and over to the passenger side lamp. Zip-tie this to the inside of the bumper as well, as we're near moving parts.
• If you aren't putting these relays into a weatherproof box, at least make sure the contacts point down to let water drain away to prevent corrosion. Keep an eye on them!
• A little dielctric grease keeps the corrosion away!

Aiming

Now that your new lights are working you've noticed that they are seriously bright. To be nice, we should aim those guys, right? Go to Stern's Lighting Page for tips on aiming E-code (euro) lights.

Questions/Comments?