oups59

Is there a procedure to bench test if the electric motors of the mirrors work well? I have a set laying around but no 928 to test them ....Those were on a 1988 S4 (p/n 944-731-027-01)

Thanks

oups59

I checked the Porsche 928 Wiring Diagram for a 1988 but the cable colors doesn't match ?

Geo55

Those wires were cut from the plug that connects to the window switches and that is why the colors don't match. I had mine apart to repair where they cut the wires and figured out out the black and white wires worked in the process when I switched over to the Saab motors. I think that each set of wires (Black and White) controlled a motor and then the switch just reversed the polarity to move in the opposite direction. Hopefully someone that has worked on them will chime in for a better understanding. I did mine in 2017. and I may have posted on that subject. Worth a search. try this https://rennlist.com/forums/928-foru...de-mirror.html

Kevin in Atlanta

Those motors are not 87 and up. More likely 85-86.

Geo55

I thought that they may operate similarly because the wire colors were the same. My Bad!

ZEUS+

Connect one lead of an ohm meter to one wire. With the other lead, touch each wire until you have a resistance value. Now you have paired the motor leads. You can supply power and ground to the wires of each pair and then reverse to test operation of each motor.

oups59

Thanks. I will try that.

oups59

This is on one of the mirror (May 1987). The tag on the other one is difficult to read.

Kevin in Atlanta

This is an 87+ mirror motor for a 928.

oups59

I think yours is a mirror with memory (Seating Position Control)? The one I have was on a car with sport seats.

If I remember correctly, the connector was round - not flat like the ones in your picture.

oups59

They works perfectly.

white/white-brown is one motor
Black/black-brown is the other one.

Alan

The mirror backing plate should have a heated glass connection pair too - A Brown wire and usually a Grey/Green wire - are those in there in the housing? other Porsche model uses of the mirror didn't always have this.

Alan