Summer finally arrived in the Northwest today, and I spent the afternoon removing the sunroof from my 940 Wagon (1993). The instructions in the FAQs section were great, and I had the sunroof out of the car in about an hour.
The gasket was nasty and green with moss, and it often slips off the flange, leaving a gap between the sunroof and the roof, so I thought I'd just replace it.
The auto parts place didn't have anything like it and Volvo doesn't seem to make a replacement anymore, so I just cleaned it up and re-installed it, and it looks great. To prevent it from drooping and slipping, I made sure the channel was clean and then squeezed it tight to narrow the channel and make it grip batter.
My 'tip' is to stretch the gasket when you're putting it back on, so the ends meet tightly.

I re-installed it and here's the question: The motor moves the sunroof forward, and then it stops about 2 inches before it's fully closed. Another push on the switch, and it closes. Then when I open it again, it opens 2 inches and stops. Another push on the switch and it opens the rest of the way.
And it won't 'vent'. It just moves forward and backward, no tilting up or down.

So, do I need to 'zero' the electric motor, per the instructions in the FAQs? Or does somebody have another idea or suggestion?