A/C Condenser Fan High Speed Circuit Troubleshooting (Manual A/C)

HVAC

A/C Condenser Fan High Speed Circuit Troubleshooting

A/C Condenser Fan High Speed Circuit Troubleshooting

NOTE:
* Do not use this troubleshooting procedure if the A/C compressor is inoperative. Refer to the symptom troubleshooting index.
* If A/C refrigerant pressure is abnormal, the radiator fans are controlled based only on engine coolant temperature.
* Before doing symptom troubleshooting, check for PGM-FI DTCs How To Troubleshoot The Fuel And Emissions Systems.

1. Fuse check:

Fuse check
-1. Check the following fuses.





Are the fuses OK?
-YES- Go to step 2.
-NO- Replace the fuse(s), and recheck. If the fuse(s) blows again, check for a short in the No. A2-10 (20 A) fuse and/or the No. A11 (7.5 A) fuse circuits.

2. A/C condenser fan relay check:

A/C condenser fan relay check
-1. Remove the A/C condenser fan relay from the under-hood fuse/relay box, and test it Testing and Inspection.

Is the relay OK?
-YES- Go to step 3.
-NO- Replace the A/C condenser fan relay.

3. Open wire check (+B_SUB_FAN line):

Open wire check (+B_SUB_FAN line)
-1. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- The +B_SUB_FAN wire is OK. Go to step 4.
-NO- An open in the +B_SUB_FAN wire. Replace the under-hood fuse/relay box.

4. SUB FAN MOTOR line check:

SUB FAN MOTOR line check
-1. Connect terminals A and B with a jumper wire.









Does the A/C condenser fan run on high?
-YES- The +B_SUB_FAN/SUB_FAN_MOTOR wires are OK. Go to step 5.
-NO- An open in the +B_SUB_FAN wire. Replace the under-hood fuse/relay box.

5. A/C condenser fan relay coil side power circuit check:

A/C condenser fan relay coil side power circuit check
-1. Disconnect the jumper wire.

-2. Turn the ignition switch to ON (II).

-3. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- No. A11 (7.5 A) fuse wire is OK. Go to step 6.
-NO- Go to step 7.

6. Open wire check (FAN_HI_SIGNAL line):

Open wire check (FAN_HI_SIGNAL line)
-1. Turn the ignition switch to LOCK (0).

-2. Reinstall the A/C condenser fan relay.

-3. Jump the SCS line with the HDS.
NOTE: This step must be done to protect the ECM/PCM from damage.

-4. Disconnect the following connector.





-5. Connect terminals A and B with a jumper wire.









-6. Turn the ignition switch to ON (II).

Does the A/C condenser fan run on high?
-YES- Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM (K24Z7 engine) Service and Repair or ECM/PCM (except K24Z7 engine) and recheck.
-NO- Repair an open in the wire between the A/C condenser fan relay and the ECM/PCM.

7. A/C diode A check:

A/C diode A check
-1. Turn the ignition switch to LOCK (0).

-2. Using the diode setting on a DVOM, check for current flow in both directions between A/C diode A terminals No. 1 and No. 2.





Is there current flow in only one direction?
-YES- An open in No. A11 (7.5 A) fuse circuit wire. Replace the under-hood fuse/relay box.
-NO- Replace A/C diode A.