Engine Compartment Fuses
 

From top to bottom, does anyone know what the three fuses in the engine compartment fuse panel protect?

Depends on the year of the car. Defrost, blower motors, relays etc.
Use the specific year's schematic print to know for sure.

In my '88 the top fuse is for the cabin heat control module, auto-heat or no.

The middle one is for the cabin heat blower in the engine compartment.

The bottom one is for the rear window defrost heating grid.

Likely the same for '84-88.

Note: if the top one is blown the 2 footwell blowers will not work.

Mine's an '86, but the Bentley manual only diagrams the luggage compartment fuses. Previous owner removed the autoheat so that wire has been disconnected. I've got two red wires going into the bottom fuse, though, and I wouldn't think a Cab would have rear window defroster wiring.

Remove the fuses and see what stops working... :)

Yup - same for 84-89 but different for the same MY 930.
Bottom also goes to Rear window wiper.
Don't know why a cab would be fused.
Bentley shows them all in the fuse tables in section 971.

Thanks! I found it. For those searching, it's 971-16 of the Bentley manual near the bottom.