98 S70. Sunroof is stuck in the closed position. Tried rocking it with the power switch and it tries to open but to no avail. Seems like something seized.

It hasn't been operated in quite a while.

Any ideas?

Frozen in place. Usually, the aluminum hinges get crusted with road salt and now there is just too much force needed to free the workings.

You could try "helping" it a little by pushing up at the rear with one hand and pushing the top of the switch with the other hand. Be prepared to have some grease/oil handy to lube the hinges.
I had mine stuck where it would not go back. Problem solved by reaching up and freeing the wind deflector and then pushing the switch down.

Klaus
--
The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)

Klaus:

Thanks so much for this. I'll get an extra set of hands and "help" it along. Is there a preferred lube for this or do I just use my pump oil can with regular engine oil?

I used a cloth with oil on it to clean things up first. Then with a Qtip, I dabbed grease on the offending parts. Oil will eventually wash off with water, grease has this staying power.

Klaus
--
The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)