The motor is a brushed DC motor so that it can run in two directions. There are two wires that run from the switch to the motor. Current (should) run through both wires whenever the SR motor is engaged, positive in one and ground via the other. All the switch does is reverse the direction of the current when the SR direction is reversed. If the motor works in one direction, there is a 95% probability that the motor is fine. The wiring also obviously must also be fine for the roof to work in any direction. Please test that you have the same voltage across both connectors (on the wire that attaches to the SR motor) first before you replace the motor ($$$), if the voltage is not exactly the same, this can indicate a bad contact! There are other ways to test this mroe accurately, but it might be a bit harder for you to test. The second test is attaching a wire to a good grounding pt. of the car and seeing if it makes a good circuit to both the connector that would attach to the SR motor.

Since you said that the motor ran slowly for a bit in the other direction, it leads me still to think that the switch contacts are the problem.

Sincerely,

ATLD