Radiator and A/C Condenser Fan Low Speed Circuit Troubleshooting
NOTE:
  • Do not use this troubleshooting procedure if the A/C compressor is inoperative. Refer to the symptom troubleshooting index.
  • Before doing any symptom troubleshooting, check for powertrain DTCs.
  1. Check the No. 18 (20 A) fuse in the under-hood fuse/relay box, and the No. 36 (10 A) fuse in the under-dash fuse/relay box.
Are the fuses OK?
YES -
Go to Step 2 .
NO -
Replace the fuses, and recheck. If fuses blow again, check for a short in the No. 18 (20 A) and No. 36 (20 A) fuses circuit.■
  1. Connect the HDS to the DLC.
  1. Turn the ignition switch ON (II).
  1. Turn on the A/C.
  1. Check the FAN LOW CTRL in the PGM-FI Data List with the HDS.
Is the FAN LOW CTRL on?
YES -
Go to Step 6 .
NO -
Substitute a known-good ECM, and retest. If the symptom/indication goes away with a known-good ECM, replace the original ECM. ■
  1. Turn the ignition switch OFF.
  1. Jump the SCS line with the HDS.
    NOTE: This step must be done to protect the engine control module (ECM) from damage.
  1. Disconnect ECM connector A (44P).
  1. Turn the ignition switch ON (II).
  1. Measure the voltage between ECM connector A (44P) terminal No. 4 and body ground.
Is there battery voltage?
YES -
Go to Step 11 .
NO -
Repair open in the wires between the under-hood fuse/relay box and the ECM, or between the No. 36 (10 A) fuse in under-dash fuse/relay box and the under-hood fuse/relay box. If wires are OK, replace the under-hood fuse/relay box. ■
  1. Turn the ignition switch OFF.
  1. Connect the ECM connector A (44P) terminal No. 4 to body ground with a jumper wire.
  1. Turn the ignition switch ON (II).
Do the A/C condenser and radiator fans run on low?
YES -
Check for loose wires or poor connections at ECM connector A (44P) terminal No. 4. If the connections are good, substitute a known-good ECM, and recheck. If the symptom/indication goes away, replace the original ECM. ■
NO -
Go to Step 14 .
  1. Turn the ignition switch OFF.
  1. Disconnect the jumper wire.
  1. Disconnect the radiator fan 2P connector.
  1. Turn the ignition switch ON (II), then set the A/C button and fan control switch ON.
  1. Measure the voltage between the radiator fan 2P connector terminal No. 2 and body ground.
Is there battery voltage?
YES -
Go to Step 19 .
NO -
Repair open in the wire between the under-hood fuse/relay box and the radiator fan. If the wire is OK, replace the under-hood fuse/relay box. ■
  1. Set the A/C button and fan control switch OFF, then turn the ignition switch OFF.
  1. Reconnect the radiator fan 2P connector.
  1. Connect the radiator fan 2P connector terminal No. 1 to body ground with a jumper wire.
  1. Turn the ignition switch ON (II), then set the A/C button and fan control switch ON.
Does the radiator fan run?
YES -
Go to Step 23 .
NO -
  1. Set the A/C button and fan control switch OFF, then turn the ignition switch OFF.
  1. Disconnect the jumper wire.
Is the relay OK?
YES -
Go to Step 26 .
NO -
Replace the fan control relay.■
  1. Turn the ignition switch ON (II), then set the A/C button and fan control switch ON.
  1. Measure the voltage between the fan control relay 5P socket terminal No. 1 and body ground.
Is there battery voltage?
YES -
Go to Step 28 .
NO -
Repair open in the wire between the radiator fan and the fan control relay.■
  1. Set the A/C button and fan control switch OFF, then turn the ignition switch OFF.
  1. Disconnect the A/C condenser fan 2P connector.
  1. Check for continuity between the fan control relay 5P socket terminal No. 4 and the A/C condenser fan 2P connector terminal No. 2.
Is there continuity?
YES -
Go to Step 31 .
NO -
Repair open in the wire between the fan control relay and the A/C condenser fan.■
  1. Check for continuity between the A/C condenser fan 2P connector terminal No. 1 and body ground.
Is there continuity?
YES -
NO -
Check for an open in the wire between the A/C condenser fan and body ground. If the wire is OK, check for poor ground at G301. ■