Main buss #30 from battery powers the headlight motor. You need to check both sides of the fuse holder to ground. You may have a bad fuse and not realize it.
Here is the head light motor schematic for the early 944's.
Mostly the same for the later 944's with some fuse number changes.
The power to the fuse comes from section 4 (IV) line 9. You will find a return pointer to section 2 (II) line 11.