TOYOTA CAMRY 1999 Service Repair Manual
Manufacturer: TOYOTA, Model Year: 1999, Model line: CAMRY, Model: TOYOTA CAMRY 1999Pages: 4592, PDF Size: 55.16 MB
Page 4521 of 4592

AIR CONDITIONING (AUTOMATIC A/C)
5. AIR CONDITIONING OPERATION
The A/C control assembly receives various signals, I.E., the engine RPM from the engine control module, out side air
temperature signal from the A/C ambient temp. sensor, coolant temperature from the engine control module and the lock
signal from the A/C compressor, etc.
When the engine is started and the A/C SW (A/C control assembly) is on, a signal is input to the A/C control assembly.
As a result, the ground circuit in A/C control assembly is closed and current flows from HEATER fuse to TERMINAL 1 of
the MG CLT relay to TERMINAL 2 to TERMINAL 3 of the diode (A/C) to TERMINAL 2 to TERMINAL MGCR of the A/C
control assembly to TERMINAL GND to GROUND, turning the MG CLT relay on, so that the magnetic clutch is on and the
A/C compressor operates.
At the same time, the engine control module. Detects the magnetic clutch is on and the A/C compressor operates.
If the A/C control assembly detects the following conditions, it stops the air conditioning:
*Evaporator outlet air is too low.
*There is a marked difference between the compressor speed and the engine speed.
*The refrigerant pressure is abnormally high or abnormally low.
*The engine speed is too low.
*Rapid acceleration occurs.
A3 A/C DUAL PRESSURE SW
4±1 : Open above approx. 2.0 kgf/cm2 (29 psi, 196 kpa) or 32 kgf/cm2 (464 psi, 3138 kpa)
A2
A/C MAGNETIC CLUTCH AND LOCK SENSOR
4±GROUND : Approx. 3.7 W
A34 (A), A35 (B) A/C CONTROL ASSEMBLY
B±GROUND : Always approx. 12 volts
IG+ ±GROUND : Approx. 12 volts with the ignition SW at ON position
HR ±GROUND : Approx. 12 volts with the ignition SW at ON position and do not turn the blower motor
Below 1 volts with the ignition SW at ON position and turn the blower motor
PSW±GROUND : Below 1 volts with the ignition SW at ON position
AC1±GROUND : Below 1 volts at start the engine, operate the compressor
+ OR MORE volts at start the engine, do not operate the compressor
BLW±GROUND : Below 1.5 volts with the ignition SW on and turn the blower motor
S5±SG :4±6 volts with the ignition SW at ON position
SG±GROUND : Always continuity
AMH±AMC :1.3±1.9 volts with the ignition SW off
AIF±GROUND : Approx. 12 volts with the FRESH SW on
AIR±GROUND : Approx. 12 volts with the RECIRC SW on
FACE±GROUND: Approx. 12 volts with the FACE SW on
DEF±GROUND : Approx. 12 volts with the DEF SW on
GND±GROUND : Always continuity
: PARTS LOCATION
CodeSee PageCodeSee PageCodeSee Page
A226 (1MZ±FE)A3630F826 (1MZ±FE)
A326 (1MZ±FE)A3730J131
A1330A3830J1131
A2030A3930J27A31
A3026 (1MZ±FE)B330J28B31
A3330B830J2931
A34A30D330J3231
A35B30E830
: RELAY BLOCKS
CodeSee PageRelay Blocks (Relay Block Location)
124Engine Room R/B No.1 (Engine Compartment Left)
SERVICE HINTS