Lew

My headlight motor still doesn't work. I have two of them, one new, with relays. The motor hooks up with 4 wires. Brown is ground, and that with gray show the full 12 volts on the multimeter. The other two show some voltage. If I direct wire the gray wire to the battery the relay clicks, but the motor never runs. Fuse is okay, I've cleaned all the connections. What am I missing? I have the Haynes manual with the wiring diagram.

Martin

If you have grey wiring I will assume you have the early car.
grey is the power feed from the headlight switch when the switch is in position two (headlights on). When the grey wire has power on it it feeds through the cam switch he headlights are not up and connects to the relay coil on the motor housing. This pulls the relay in and connects the positive side of the motor to the red/blue wire which must have power on it to feed the motor. So the grey wire is the signal to raise the headlights but it doesn't power the motor, the red/blue wire is the fused feed to the motor via the relay.
hope this helps.

Tiger03447

So, if the red blue wire makes the headlights go up when it feeds 12V, does the red green wire make them go down again when it gets 12V?

orig944

Old cars (New cars in parenthesis)

The Grey (Yellow/Blue) wire powers the relay coil if the light switch is on and the wiper in the motor on that terminal is making contact, which it does everywhere except when the lights are all the way up. The Red/Green (Red/Green) wire powers the relay coil if the switch is off and the wiper in the motor on that terminal is making contact, which it does everywhere except when the lights are all the way down. The Red (Red/Blue) wire powers the motor when the relay is activated.

orig944

I should add, if the light switch is in the middle position, neither the Grey or Red/Green wire is powered. So if the lights are up, they stay up, and if they are down, they stay down.

944Thomas

Did you get this resolved? I was having the same issue with my 86. I checked the fuse and didn't realize the mechanism has three separate fuses. I checked all three and found one was blown. Works like a champ now. Hope this helps.

Tiger03447

Glad you got it to work. Good to also know that they put 3 fuses in the revised circuit. They were unfused in the early cars. Read Zirconene’s recent post about his early headlight switch. This may be why Porsche went to another switch design in the later cars.