A/C Condenser Fan High Speed Circuit Troubleshooting (Climate Control)

HVAC

A/C Condenser Fan High Speed Circuit Troubleshooting (Climate Control)

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 and A/C condenser 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:

-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) blow again, check for a short in the No. A2-10 (20 A) fuse and/or the No. A8 (7.5 A) fuse circuit(s).

2. 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):

-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 Under-Hood Fuse/Relay Box Removal and Installation.

4. 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 SUB FAN MOTOR wire is OK. Go to step 5.
-NO- Repair an open in the wire between the A/C condenser fan relay and the A/C condenser fan motor.

5. 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- The No. A8 (7.5 A) fuse circuit wire is OK. Go to step 6.
-NO- Go to step 7.

6. 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 PCM from damage.

-4. Disconnect the following connector.






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














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

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

7. 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 the No. A8 (7.5 A) fuse circuit wire. Replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal and Installation.
-NO- Replace A/C diode A.