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For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2000 🢒 Isuzu MD Steel Tilt (F Model) 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 HVAC Compressor Clutch Does Not Engage

Step

Action

Value(s)

Yes

No

1
  1. Locate the vehicle in an area with ambient air temperature greater than 10°C (50°F).
  2. Start the engine and maintain at 1000 rpm.
  3. Place the A/C mode switch in the ON position.
  4. Place the fan control switch in position 1.
  5. With the blower motor operating, place the fan control in position 4.
  6. Place the temperature control lever, on the A/C mode switch, in the full left COLD position.
  7. Observe if the A/C compressor clutch engages during a 5 minute observation period and cold air is produced.

Does the A/C compressor clutch engage?

--

Go to Step 31

Go to Step 2

2
  1. Place the fan control switch in position 1.
  2. Remove the A/C compressor clutch relay from the relay socket.
  3. Connect a fused jumper wire between terminal 30 and terminal 87 in the A/C compressor clutch relay socket.

Does the A/C compressor clutch engage?

--

Go to Step 3

Go to

Step 11

3
  1. Connect a J 39200 DMM between terminal 86 in the compressor relay socket and chassis ground.
  2. Set the window washer switch to the ON position.

Does the DMM indicate continuity?

--

Go to Step 4

Go to Step 5

4

Connect a test lamp between the A/C compressor relay socket terminal 85 and chassis ground.

Does the test lamp light?

--

Go to Step 6

Go to Step 7

5

Repair the open CKT 211 (GRN/RED) between S307 and terminal 86 in the compressor relay socket.

Is the repair complete?

--

System OK

Go to Step 4

6
  1. Install the compressor relay into the relay socket.
  2. Place the window washer switch in the ON position.

Does the compressor clutch engage?

--

Go to Step 8

Go to Step 9

7

Locate and repair the open in the CKT 210 (LTGRN) wire between terminal 87 in the blower relay and terminal 85 in the A/C compressor relay.

Is the repair complete?

--

System OK

Go to Step 6

8
  1. Disconnect the harness connector from the evaporator temperature sensor.
  2. Connect a fused jumper between terminal A and terminal B in the evaporator temperature sensor harness connector.

Does the A/C compressor clutch engage?

--

Go to Step 10

Go to Step 11

9

Replace the compressor relay.

Is the repair complete?

--

System OK

Go to Step 8

10
  1. Make sure the evaporator icing condition does not exist.
  2. Replace the evaporator temperature sensor.

Is the repair complete?

--

System OK

Go to Step 11

11

Connect a fused jumper between terminal A in the evaporator temperature sensor harness connector and chassis ground.

Does the A/C compressor clutch engage?

--

Go to Step 12

Go to Step 13

12
  1. Connect a jumper between terminal B in the evaporator temperature sensor harness connector and chassis ground.
  2. Remove the D201 diode module.
  3. Connect a J 39200 DMM between terminal E in the D201 diode module harness connector and chassis ground.

Does the DMM indicate continuity?

--

Go to Step 14

Go to Step 15

13

Locate and repair open in CKT 18/213 (GRN/RED) between S 307 and terminal A in the evaporator temperature sensor.

Is the repair complete?

--

System OK

Go to Step 12

14
  1. Disconnect the harness connector  C2 from the A/C mode switch.
  2. Connect a jumper between terminal  3 in the A/C mode switch harness connector  C2 and chassis ground.
  3. Connect a J 39200 DMM between terminal F in the D201 diode module harness connector and chassis ground.

Does the DMM indicate continuity?

--

Go to Step 16

Go to Step 17

15

Locate and repair open in CKT 17/215 (GRN/YEL) between terminal E in the D201 diode module harness connector and terminal B in the evaporator temperature sensor harness connector.

Is the repair complete?

--

System OK

Go to Step 16

16

Inspect diode D201.

Is diode D201 in good condition?

--

Go to Step 18

Go to Step 19

17

Locate and repair open in CKT 177/216 (GRN) between terminal F in the D201 diode module harness connector and terminal 3 in the A/C mode switch harness connector.

Is the repair complete?

--

System OK

Go to Step 16

18

Replace the A/C mode switch. Refer to Control Assembly Replacement .

Is the repair complete?

--

System OK

Go to Step 19

19

Replace the diode module.

Is the repair complete?

--

System OK

Go to Step 20

20

Connect a test lamp between the A/C compressor clutch relay socket terminal 87 and chassis ground.

Does the test lamp light?

--

Go to Step 21

Go to Step 22

21

Connect a J 39200 DMM between the A/C compressor clutch relay socket terminal 87 and chassis ground.

Does the DMM indicate continuity?

--

Go to Step 23

Go to Step 24

22

Locate and repair open in CKT 201/207 (GRN/RED) between circuit breaker 20 and terminal 30 in the A/C compressor relay socket.

Is the repair complete?

--

System OK

Go to Step 21

23

Replace the compressor clutch relay.

Is the repair complete?

--

System OK

Go to Step 24

24
  1. Disconnect harness connector from the A/C pressure cut-off switch.
  2. Connect a J 39200 DMM between terminal 87 in the A/C compressor relay socket and terminal 3 in the A/C refrigerant pressure cutoff switch connector.

Does the DMM indicate continuity?

--

Go to Step 25

Go to Step 26

25

Connect a J 39200 DMM between terminal 4 in the A/C refrigerant pressure switch harness connector and chassis ground.

Does the DMM indicate continuity?

--

Go to Step 27

Go to Step 28

26

Locate and repair the open in CKT 203/208 between terminal 87 in the A/C compressor relay and terminal 3 in the A/C refrigerant pressure cutoff switch.

Is the repair complete?

--

System OK

Go to Step 25

27
  1. Charge the A/C system with freon. Refer to Refrigerant Recovery and Recharging .
  2. Replace the A/C pressure cutoff switch.

Is the replacement complete?

--

System OK

Go to Step 28

28
  1. Disconnect the harness connector from the A/C compressor clutch.
  2. Connect a J 39200 DMM between the A/C compressor clutch terminal and chassis ground.

Does the DMM indicate continuity?

--

Go to Step 29

Go to Step 30

29

Locate and repair open in CKT 6/59 (DK GRN) between terminal 4 in the A/C refrigerant pressure switch harness connector and the A/C compressor clutch harness connector terminal.

Is the repair complete?

--

System OK

Go to Step 30

30

Repair or replace the A/C compressor clutch. Refer to Compressor Magnetic Clutch .

Is the repair complete?

--

System OK

--

31

Refer to System Performance Test .

Is the problem resolved?

--

System OK

--