Honda Acura NSX 1991 Service Manual page 1102

Cooling Fan Control
Fan control system:
The cooling fan,system is comprised of radiator fan, condenser fan (left, right), engine compartment fan, radiator fan
low relay radiator fan high relay, condenser fan relay, engine room fan relay, radiator fan resistor, coolant temperature
sensor, A/C pressure switch, cooling fan control unit, climate control unit and PGM-FI ECU.
The fan control unit controls the operation of the radiator fan and condenser fan.
It uses inputs from the coolant temperature sensor and A/C pressure switch (A and B) on the A/C system to determine
when the fans should run and at what speed.
Additionally the temperature switch shuts down the A/C system if the coolant temperature exceeds 1 30°C (266OF).
If the pressure in the A/C system is higher than normal, pressure switch A closes and the fans will run at high speed only.
See the A/C section for description and specification of that funciton.
Function
Operating Condition
At low speed
At high speed
Fans operating condiiton:
Operating condition
Fans
Radiator fan motor
Engine compartment
fan motor
23-l 16
ON
1 30°C (266OF)
At low speed At high speed
ON
OFF
OFF
ON
ON