Isuzu 4JA1 Workshop Manual page 418

6E-164 Engine Control System (4JH1)
Step
6 1. Turn OFF the ignition.
2. Remove the A/C compressor relay.
3. Connect a test lamp between the voltage feed
circuit of the A/C compressor relay coil side (pin
3 of X-14 connector) and a known good ground.
4. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?
7 1. Turn OFF the ignition.
2. Connect a
compressor relay control circuit (pin 5 of X-14
connector) and battery voltage.
3. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?
8 1. Keep the test lamp with connected.
2. Start the engine.
3. Turn ON the blower motor switch and the A/C
compressor switch.
Does the test lamp illuminate when the A/C
Compressor Relay parameter is ON?
9 Repair the open circuit or high resistance on the
voltage feed circuit between the ECM (10A) fuse
(EB-4) and the A/C compressor relay (pin 3 of X-14
connector).
Did you complete the repair?
10 1. Test the control circuit of the A/C compressor
relay between the ECM (pin 38 of C-56
connector) and the A/C compressor relay (pin 5
of X-14 connector) for a short to ground.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
11 1. Test the control circuit of the A/C compressor
relay between the engine control module (ECM)
(pin 38 of C-56 connector) and A/C compressor
relay (pin 5 of X-14 connector) for an open circuit
or high resistance.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
12 1. Turn OFF the ignition.
2. Inspect for
connections on the A/C compressor relay
terminal (pins 3 and 5 of X-14 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
13 1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for a poor
connection on the A/C compressor relay control
circuit at the harness connector of the ECM (pin
38 of C-56 connector).
4. Repair the connection (s) as necessary.
Did you find and correct the condition?
14 Replace the A/C compressor relay.
Did you complete the replacement?
Action
test lamp between the
an intermittent and for
Value(s)

A/C





poor



Yes
Go to Step 7 Go to Step 9
Go to Step 10 Go to Step 8
Go to Step 12 Go to Step 11
Go to Step 16
Go to Step 16 Go to Step 15
Go to Step 16 Go to Step 13
Go to Step 16 Go to Step 14
Go to Step 16 Go to Step 15
Go to Step 16
No

