Carrera sunroof motor in 911T issue

[runner4fun]

OK: I have only basic wiring skills.

I seem to send more time fussing with my sunroofs. I have a 1973 911T factory sunroof coupe. It's a shell i am restoring it with a mild hot rod RS theme. The sardine can sunroof motor is failing, squeals at slow speed when powered. I have 2 perfect Rockwell Carrera sunroof motors that work perfectly. I modified the mounting bracket to the Carrera motor and installed one in the car. It lines up well with the triangular transmission that drives the cables.

The old motor had 2 power wires and a separate ground wire. The carrera motors do not have a ground wire. Apparently, the Carrera motor wires alternate between positive and ground when the motor direction is changed.

My switch is good, I have power at the motor, but the Carrera motor will not turn. What wiring change do i need to make so the Carrera motor will work in the 911T?

Thanks for any help.

[runner4fun]

The answer is that the 3 pin on the switch and connector is a ground on the SC and Carrera sunroof harness. The earlier cars do not have a ground at that pin because the sunroof motor is separately grounded. I checked a Carrera sunroof harness and it has a a ground at the 3 pin. Below is the sunroof wiring diagram showing the ground at the 3 pin position. I will add a ground at the 3 pin on the connector and that should solve the issue.

https://www.early911sregistry.org/forums/attachment.php?attachmentid=366322&stc=1&d=1454287819