Mitsubishi 3000GT 1991 Service Manual page 188

13-82
FUEL SYSTEM
AIR CONDITIONER SWITCH AND POWER RELAY
OPERATION
The air conditioner switch applies the battery voltage to the engine control unit when the air conditioner is
l
turned on.
When the air conditioner ON signal is input, the engine control unit drives the idle speed control servo and
l
turns ON the power transistor. As a result, the air conditioner power relay coil is energized to turn on the
relay switch, which activates the air compressor magnetic clutch.
TROUBLESHOOTING HINTS
If the air compressor magnet clutch is not activated when the air conditioner switch is turned on during idling,
faulty air conditioner control system is suspected.
INSPECTION
Using Multi-use Tester
AIR CONDITIONER SWITCH
Function
Data reading 28
Air conditioner
control unit
Air conditroner
r
Engine control unit
Engine control unit connector
Check condition
Switch state Engine: Idling (air
compressor to be running
when air conditioner
switch is ON)
TSB Revision
Air conditioner
compressor lock
controller
Dual pressure
switch
OFF
ON
Air conditioner
compressor
OFF
ON