Hi,

This is a follow up to my post on the same subject earlier this week. I'm in the process of wiring the headlights (Euro) so they're powered by the battery with relays. I bought the kit to do this from Dan Stern.
I have a good understand of how the relays work, but I'm still confused about the 9004 male adapters that come with the kit. The plug has three leads. I assume one for high beams, one for low, and the last for the ground. Do I run three wires from each 9004 male adapter to the inputs on the relays? For instance, one to the high beam relay, one to the low beam relay, then one to a ground? If so, where exactly would I ground it?

Also, on the 9004 plugs, how do I distinguish the low/high leads?

Thanks!
--
crazy driving: Cincinnati, OH, 1993 244 Limited Ed. 'Classic' model (daily driver). 65,xxx k. Mods: ipd sway bars, strut to firewall braces, Bosch amber fog lights, 52mm tach.

Hi, again.

If I remember right, here's how it is:

If you look down from above at the 9004 plug (as it's in its normal position, plugged into the bulb), the three contacts are like this (right is passenger side, left is drivers side):

right most: high beam
middle: low beam
left most: ground

I also seem to remember that the 9004 wires, into the plug, were red (high), blue (low), and black (ground).

Same with the H4's plugs (held in its normal position, as plugged into the bulb):
right (vertical blade): high beam
middle (horizontal blade): low beam
left (vertical): ground

Of course, please use a VOM or 12v test light just to be sure -- it's been about two years since I wired my cars for Euroheadlights) -- but I think I'm right.

Have fun.

Yes, Ken C's notes match my recollection:

right most: high beam
middle: low beam
left most: ground

Left and right above being the left and right side of the car, with bulb installed or at least correctly oriented.

The part I can't recall is whether the horizontal center contact ends up at the top or bottom of the layout. But you can determine that easily when you look at the imprint on the front of the bulb. Lettering goes right side up.

For anyone working with the smaller 4" x 6" sealed-beam bulbs, the pinout on those sealed beam bulbs is different. All H4s are the same of course, it's the USA 4" x 6" sealed beams and their connectors on the cars that don't match the H4s. Stern and rallylights.com both provide adapters if you buy e-code setups from them; or you can probably buy the adapters or make your own if you need them.
--
Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.

Somewhere in the middle of this wacko page, there are some figures to help ID the connector pin-outs:

http://oak.cats.ohiou.edu/~ridgely/e-code.htm

As for the ground in the 9004 plug, you can either ground one of your relays (pin 85 on the relay) to it, or not attach anything to it. From the original plug in the car, it grounds to the chassis... so in an electrical sense, that ground wire is just an extension of the car itself. :)

For safety, I like to keep the hi and low beam circuits completely seperate (i.e. don't share grounds), that way if something happens to say, the low beams, you always have the high's to get you safely to the side of the road.

-Ryan

--
--------------------------
Athens, Ohio
1990 245 DL 130k M47, E-codes
1991 745 GL 280k (Girlfriend-mobile)
Buckeye Volvo Club

I'm sorry I don't have good notes saved from my work. I'll go from memory.

The male pins going into the car's existing 9004 plugs will go to the relays, activating the coils inside the relays. You can use the ground wire in that male pin set as the coil ground at the relays. However if it's more convenient to provide your own ground that's just as good. Better maybe, since you'll know where the ground is and can check it if needed.

A voltmeter should tell you which of the three connectors is which. One will be hot when the car is set for low beams, one hot when set for high, and the ground terminal will never be hot but will show 0 ohms resistance when checking continuity to any known good ground.

Now as for the pinout for the H4 bulb.

The only thing I can tell you for certain is that the center pin is NOT the ground. The ground is one of the end pins.

I figured it out with the ohmmeter.

Check ohms across the available combinations of two pins. Find the two pins that give the highest resistance. The ground is the third pin, the one not in that high-resistance pair.

Now, measure ohms from the ground pin to each of the two others, one at a time. The higher wattage pin will show slightly less ohms resistance; the lower wattage pin (low beam) will show slightly higher resistance.

For this last check above, make sure you have a good clean solid connection for your readings. The difference will be very slight as there is not much wattage difference in the high beam vs. low beam filament. You can always test by installing using a quickie twisted-wire connection. The ground wire test that I gave is very reliable as long as your ohmmeter can read those low resistance levels (just a few ohms).

Good luc!
--
Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.