Engine Electrical System

10) A/C system malfunction
Yes Proceed to next step.
1
Verify that there is enough refrigerant and
the A/C belt, A/C clutch and pressure switch
are in good condition.
No Fix the malfunction.
Yes
Fix the indicated
malfunction.
2
Run the engine at idle speed and turn on the
A/C switch. Inspect with the diagnostic
tester to see whether there is any
malfunction with the A/C thermo-sensitive
resistance.
No Proceed to next step.
Yes Proceed to next step.
3
Turn on the A/C switch and connect the
adaptor between ECU and the wiring
harness. Measure and see whether the
ECU’s A/C switch and A/C pressure have
any signal input.
No
Inspect the wiring
harness.
Yes
Replace the bulb or
repair the wiring
harness.
4
If the car is controlled by low electrical
level, verify that the A/C still functions
when it is turned off.
No Proceed to next step.
Yes
Repair the A/C relay
and the wiring
harness.
5
Verify that there is any low level output
from the ground terminal of A/C relay
solenoid coil in ECU.
No Replace the ECU.
E-78
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