Date registered: Jul 2004
Vehicle: 1991 500SEC 38,800 mi. 1987 560SEC Now 145K mi. (Spring 2017)
Location: Boston, MA area
Mentioned: 0 Post(s)
Quoted: 164 Post(s)
RE: Looking for wiring diagram of AC/Heat blower motor system
I think you've already found the problem, which is pretty common. There was/is something causing a poor connection at the fuse to fuse clip.
On your car, It appears that fuse 11 feeds the ACC blower fan. It is a 25 amp fuse (blue).
If the fuses in your car have aluminum over the ceramic/plastic, it might be a plan to replace them with the copper/brass ones, as the two dissimilar metals tend to corrode over time.
Enclosed is the diagram you request with some festive orange dots denoting the current flow through the blower motor.
An American company, BUSS makes fuses that will work well in our cars. They have a glass envelope with conical nickel plated ends instead of the metal connector clipped over a ceramic or plastic body.
The BUSS part numbers carry the suffix GBC, followed by the amperage rating (GBC-8 refers to 8 amps, GBC-25 >25 amps etc.).