I have been running around the internet for just a simple engine bay fuse panel diagram layout, labeled and listed would be the best. My sticker on my panel cover is ruined and my computer is to old to download a bentley.
The reason behind me getting a diagram is because I need to get my quattro working for the harsh winters, the previous owner pulled out the fuse or relay, I believe the quattro is controlled by a 15 or 25 amp fuse in position #32 but my panel is fairly old and dirty and I cant read the numbers.
Your car has a mechanical Quatro system with a Torsen type center differential. If you have a 1993 (B4) the electrical aspect of the system is just a vacuum operated rear differential lock selected by the switch in the center console, controlled by a rear diff module under the rear seat. I believe in 1993 this was powered from the ABS relay, with the rear differential module or switch sending a signal to the ABS to deactivate. Above 15mph the rear differential lock is then deactivated. Up to 1992 fuse 12 powered the rear diff system as well as reverse lights. 1993 and up I think its powered from the ABS relay, also check fuse 14. Is the ABS system functioning? or is the light on? If the ABS system is not powered it will affect the differential lock, but not the Quatro system itself (the mechanical center diff) will still work. I hope this helps.