The weather is warming in Atlanta - so forget about glow plugs, this week it's the sunroof. I've searched the forum posts on sunroof problems and there seems to be divided opinion about DIY repairs. What is the collective wisdom on my problem? Or should I turn this over to more experienced minds and fingers?

A few weeks ago when it was bitter cold, the sunroof motor switch on the dash was stuck in an "on" position. The motor hummed and nothing happened. I actually thought it was the car antenna motor making the noise so it took me about 25 minutes to locate where/what the motor hum was and I disconnect the power to the sunroof motor.

Yesterday (it is warmer now in Atlanta) I connected the power again and found that although the motor still made a noise when I engaged the dash switch, there was no action forthcoming from the sunroof. Just a motor whirr. It happens whether the switch is flipped in the "open" or "close" roof poisition. I can wrench the roof open or closed manually using the emergency socket on the motor. (There is some oil around the cable housing tube that comes out the back of the motor. Otherwise I see nothing else wrong.)

It seems to me that the cable has somehow stopped doing its job - could it be the clutch mechanism? the cable? Where should I try first? Or should I drive up the highway to the professionals? Is this an expensive repair?

The car is a 1984 300D Turbo with 179,000 miles.