rear hatch release
 

on my us 1985 928s, both hatch release switches went from doing nothing to both making a whirring noise when pulled up.
however the hatch does not release.
any suggestions?

it sounds like the either the male portion needs an adjustment or the female portion does or both.. SO , get a helper and have them pull up one of the hatch switches while you look into the female portion.
You will see a wedge part cycle through the hole,
there is an adjustment on the front side of the hatch bracket 2 10mm screws up or down, this will add more or less to the throw of the wedge.
Next if it looks like the lower portion is working, then get a ziptie and cut it the width of the male portion loosen the bolts and place the ziptie along the rear edge of the male portion this will lever the front edge closer to the moving wedge in the lower portion of the lock, close the hatch and see if the hatch now works.
If the motor only runs when the switch is pulled up and stops when its released, ( but will not complete a full cycle ), then check the 1 amp fuse at the CE panel, its blown