H4 bulb wiring positions?

[JFairman]

I am wiring in H4 bulb plugs on an '87 930 so I can use H4 Headlights in this car.
The '87 cars came with DOT H5 headlights which I do not like compared to the much better focused Euro H4 lights..
I know which wires in the car do what from a test light, but I do not know which terminals on the back of the H4 bulb are ground, high beam, and low beam.
You can touch wires to the terminals on the bulb and get filiments to light, but unless it's mounted in the reflector and on the car it's hit and miss to maybe get it right and I want to do them right the first time and solder the wires.
The H5 plugs will remain so I can put the H5 units back in if desired.

When looking at the back of the bulb while mounted in the reflector there is one terminal on top, one on the left and one on the right.

Does anyone know which of these terminals on an H4 bulb are ground, high beam filiment and low beam filiment?

[Wil Ferch]

From work I did converting other cars to H4..here is what I found and I hope is universal for ALL H4's ....

As you hold and view the backside of a H4 bulb...there are three pins in a "U" shaped pattern that stick out and face you. Right side vertical is ground....left side vertical is high beam....and bottom horizontal is low beam...

CAUTION.....this is viewing the backside of a bulb...NOT the female receptacle-end of the receiver-plug...which would be mirror-image....

- Wil

[imcarthur]

A nice drawing in this thread:

H4 Socket Wiring

Ian

[JFairman]

In the link to an earlier thread there is a diagram of the bulb connections that answered my question perfectly.

thanks.

[imcarthur]

Note: I just checked & the picture is the reverse of what Wil said. That is dangerous, because Wil is seldom wrong. The left/right is reversed as if the diagram is looking at the socket. I will check & report.

Ian

[imcarthur]

This is how mine is wired. It matches the diagram in the link (reversed).

Ian

[derkpitt]

I know this is correct,