Honda Acura NSX 1991 Service Manual page 896

Description
Cooling Fan Control Unit
Constraction
The cooling fan control unit performs calculations on the basis of signals from the water temperature sensor and controls
the operation of radiator fan speed (Hi-Low), engine compartment fan, condenser fan and A/C system.
. TEMP 1: When radiator coolant temperature is above 183°F (84"(I), the control unit operates Trl ON and radiator
fan at low speed.
When radiator coolant temperature is above 194OF (90°C), the control unit operates Trz ON, radiator fan
. TEMP 2:
at high speed and engine compartment fan.
When radiator coolant temperature is above 266OF (1 30°C), the control unit operates Tr3 OFF and stops
. TEMP 3:
the condenser fan. Then it operates Tr4 OFF and stops the compressor.
ON
O F F
ON
O F F
ON
O F F
WATER
TEMPERATURE
SENSOR
22-8
T
, A D I A
I
GND
RADIATOR FAN (Low)
T O R F A
,
ENGINE ROOM FAN
CONDENSER FAN
I
PGM-FI ECU (ACS)
N