Auxiliary Fan

The auxiliary fan is a three stage operation as introduced on the 1996 E38.

1. Stage 1:  Activated simultaneously with the compressor with an ambient air temperature >10°C (50°F). If the coolant temperature rises to >91°C the fan will also be switched on. Fan Speed = 1250 RPM.
2. Stage 2:  Activated when the medium pressure switch on the receiver/dryer closes at 17.5 bar. Fan Speed = 2000 RPM.
3. Stage 3:  Activated when the coolant temperature reaches 104°C at the double temperature switch. The stage 3 switched voltage circuit is protected by a 50 amp remote fuse (red). The fuse is located in the electrical carrier forward of the glove box.
   Fig 1: Auxiliary Fan Circuit Diagram

   Courtesy of BMW OF NORTH AMERICA, INC.