Grant Joel

Hi Guys, new to this site so any info you can give would be greatly appreciated. I have a CLK w208 with roof problem. When I go to retract the roof, the windows go down as they should when I unlock the roof, the head restraints go down with the button and the bow lock unlocks the hood (all good so far) but after that the pump just runs for like 10 seconds but the rear glass does not go up to allow for the next operation. It just sits there until eventually the pump times out and I have to reset the ignition. The pump has plenty of fluid and I have changed the relay. What could be causing the rear glass in the roof to not move upwards to allow for the bow to lift ? Any ideas ?
Thanks
Grant