Isuzu 4JA1 Workshop Manual page 485

Step
16 1. Keep the ignition ON, with the engine OFF.
2. Keep 3-amp fused jumper wire with connected.
3. Disconnect A/C compressor clutch harness
connector.
4. Connect a test lamp between A/C compressor
voltage feed circuit (E-3) and a known good
ground.
Does the test lamp illuminate?
17 Repair the open circuit or high resistance on the
relay switch side voltage feed circuit between the
A/C compressor relay (pin 1 of X-14 connector) and
the A/C (10A) fuse (EB-13).
Did you complete the repair?
18 Repair the open circuit or high resistance on the
relay switched voltage supply circuit between the
A/C compressor relay (pin 2 of X-14 connector) and
the A/C compressor clutch (pin 1 of E-3 connector).
Did you complete the repair?
19 1. Turn OFF the ignition.
2. Inspect for
connections
terminals (pins 3 and 5 of X-14 connector).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
20 1. Turn OFF the ignition.
2. Inspect for an intermittent and for a poor
connection at the harness connector of the A/C
compressor clutch (E-3).
3. Repair the connection(s) as necessary.
Did you find and correct the condition?
21 Replace the A/C compressor relay.
Did you complete the replacement?
22 Replace the A/C compressor. Refer to Heating and
Air Conditioning section.
Did you complete the replacement?
23 1. Reconnect all previously disconnected fuse,
relay or harness connector(s).
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Turn ON the blower motor switch.
Does the blower motor turn ON and operate
correctly?
Chart 2 of 2
Step
1 1. Turn OFF the ignition.
2. Replace the thermo relay with the horn relay or
replace with a known good relay.
3. Turn OFF the blower motor switch.
4. Turn OFF the A/C switch.
5. Turn ON the ignition, with the engine OFF.
Does the A/C Request Signal parameter indicate
OFF?
Action
an intermittent and
at the A/C compressor
Action
Value(s)



for poor
relay





Value(s)

Engine Control System (4JH1) 6E-231
Yes
Go to Step 20
Go to Step 23
Go to Step 23
Go to Step 23
Go to Step 23
Go to Step 23
Go to Step 23
Refer to Applicable
Diagnostic Chart in
Go to Step 4
Yes
Go to Step 33
No
Go to Step 18


Go to Step 21
Go to Step 22


Heating & Air
Conditioning
Section
No
Go to Step 2