headlight motor

[zdaxxy]

I need to test 914 headlight motor on bench. No wire harness in car. Its stripped atm.

Motor with relay. Red, green, grey.. before I randomly start plugging a car battery to this and letting out the magic smoke can someone tell me about these wires?

Red 12v always on?
green 12v momentary via switch?
grey ground?
thats my first guess, ideas?

Wouldve been nice if the harness was with car when I got u t, wouldve put a meter on those wires and marked them.

[John Rogers]

Several things to try, first print out colored electrical diagrams for your year. Since they take more than one sheet, carefully fasten them together so the diagram is once piece. Then find the tech article(s) and electrical questions posts on here and the other two 914 sites and read them through. After a while it will show things such as the ground wires are nearly always brown unless someone did repairs. Next are the relays and if you look at the diagram you made you find Porsche, in the old days fortunately used pretty standard ones. On the pin side there will be numbers, one is the trigger, one is power, one is ground and one goes to source. There are some weird ones now and then but you will have to read the diagram and see what number does what.

This may take a while and I imagine Dave D will chime in with the exact wires but will probably suggest something similar to do. To help confuse things, Porsche would stick in a wire harness at times if they had some left over so it is possible to see 73 harness in a 74 or 75 but rare. In most cases colors are standard for the various major parts.

[Dave at Pelican Parts]

Electrical diagrams can be found here: Pelican Parts - Porsche 914 Electrical Diagrams

(They've been made harder to search for, sadly--you have to look in "914 parts diagrams" and scroll down to the bottom.)

Anyway, if my reading is correct, there is a SOLID green that supplies the power to the motor. There should be a ground connection as well, possibly just a lug on the housing of the motor, which would get a brown wire plugged into it. If you just want to see if the motor runs, then hook +12V to the green wire and ground the housing, if you cannot find the brown wire. (This green wire, and possibly another wire or two, may be hidden inside the assembly.)

From your listing of the wire colors, you appear to have a 74+ car. I'm most familiar with the 74 wiring diagrams (my car is a 74) so I'll use those for the following:

The wires you talk about are ones that go to the whole headlight motor assembly, not just the motor. Most are used by the relay to control the motor; the relay does that by powering the solid green wire. The red wire gets unswitched +12V from fuse #12 which gets it straight from the battery. The gray wire and the green/black wire (check for a black stripe on your green wire that you found!) carry the "open now" and "close now" signals from the headlight switch. I am not sure which is which, but it looks like the gray is "open now" and the green/black is "close now".

If you have the whole assembly, including the relay, hooked up, you need to find the ground point (brown wire) and ground that, hook constant +12V to the red wire, and then you can hook up +12V to the gray wire. If I'm correct, the motor will run for about a second and then stop. (It will run however long it takes to move the headlight linkage to the point where the light is up.) Then you can unhook the +12V from the gray wire, and hook it up to the green/black wire. The motor should run for the same amount of time, which would be to lower the light.

I hope this helps.

--DD

[zdaxxy]

Yes, that helps a lot and my car is a 1974 based on the faded paper vin sticker on the drivers door jam. Many thanks for an excellent time saving answer!!