( TL19E00G10100012101FAAT00 )

A/C Signal Circuit Troubleshooting

NOTE:

- If the blower motor does not run at all speeds, the A/C compressor will be inoperative. Run the self-diagnostic function, and check the DTC B1241. Before performing any other troubleshooting, repair the cause of the inoperative blower motor.
- Do not use this troubleshooting procedure if any of the following items are operative; condenser fan, radiator fan, A/C compressor, or if the heater is inoperative. Refer to the symptom troubleshooting index.
- Before doing symptom troubleshooting, check for powertrain DTCs, R20A3 engine model, K24Z3 engine model. Also check for B-CAN codes.

1. Turn the ignition switch to ON (II).

1. Check if the blower motor operates at all speeds.

Does the blower motor operate at all speeds?

YES | - | Go to Step 3 .
NO | - | Repair the problem in the blower motor circuit.■

1. Turn the ignition switch to LOCK (0).

1. Disconnect climate control unit connector A (28P).

1. Turn the ignition switch to ON (II).

1. Measure the voltage between climate control unit connector A (28P) No. 21 terminal and body ground.

Is there battery voltage?

YES | - | Go to Step 7 .
NO | - | Go to Step 8 .

1. Measure the evaporator temperature sensor resistance between climate control unit connector A (28P) No. 23 terminal and connector B (12P) No. 10 terminal.

Is the resistance less than 24 kΩ?

YES | - | Check for loose wires or poor connections at climate control unit connectors. If the connections are good, substitute a known-good climate control unit and recheck. If the symptom goes away, replace the original climate control unit .■
NO | - | Test the evaporator temperature sensor. ■

1. Disconnect the A/C compressor 3P connector.

1. Measure the voltage between the A/C compressor 3P connector No. 3 terminal (R20A3 engine model) or No. 2 terminal (K24Z3 engine model) and body ground.

Is there battery voltage?

YES | - | Go to Step 10 .
NO | - | Go to Step 12 .

1. Turn the ignition switch to LOCK (0).

1. R20A3 engine model: Measure the voltage between the A/C compressor 3P connector No. 1 and No. 3 terminals. K24Z3 engine model: Measure the voltage between the A/C compressor 3P connector No. 1 and No. 2 terminals.

Is there continuity?

YES | - | Repair open in the wire between the A/C compressor and the climate control unit.■
NO | - | Replace the thermal protector.■

1. Measure the voltage between the driver's under-dash fuse/relay box connector F (33P) No. 5 terminal and body ground.

Is there battery voltage?

YES | - | Repair open in the wire between the A/C compressor and the MICU.■
NO | - | Check for loose wire or poor connections at driver's under-dash fuse/relay box connector F (33P) No. 5 terminal. If the connections are good, substitute a known-good MICU and recheck. If the symptom goes away, replace the original MICU .■