Radiator and A/C Condenser Fan Low Speed Circuit Troubleshooting
NOTE: Before doing any symptom troubleshooting, check for powertrain DTCs.
  1. Check the No. 18 (30 A) fuse in the under-hood fuse/relay box.
Is the fuse OK?
YES -
Go to Step 2 .
NO -
Replace the fuse, and recheck. If the fuse blows again, check for a short in the No. 18 (30 A) fuse circuit.■
  1. Connect the HDS to the DLC.
  1. Turn the ignition switch ON (II).
  1. Turn on the A/C on the heater control unit.
  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 No. 2 (58P).
  1. Turn the ignition switch ON (II).
  1. Measure the voltage between ECM connector No. 2 (58P) terminal No. 53 and body ground.
Is there battery voltage?
YES -
Go to Step 11 .
NO -
Repair open in the wire between the under-hood fuse/relay box and the ECM. If the wire is OK, replace the under-hood fuse/relay box. ■
  1. Turn the ignition switch OFF.
  1. Connect the ECM connector No. 2 (58P) terminal No. 53 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 No. 2 (58P) terminal No. 53. 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 A/C condenser fan 2P connector.
  1. Turn the ignition switch ON (II).
  1. Measure the voltage between the A/C condenser fan 2P connector terminal No. 2 and body ground.
Is there battery voltage?
YES -
Go to Step 18 .
NO -
Repair open in the wire between the under-hood fuse/relay box and the A/C condenser fan. If the wire is OK, replace the under-hood fuse/relay box. ■
  1. Turn the ignition switch OFF.
  1. Reconnect the A/C condenser fan 2P connector.
  1. Connect the A/C condenser fan 2P connector terminal No. 1 to body ground with a jumper wire.
  1. Turn the ignition switch ON (II).
Does the A/C condenser fan run?
YES -
Go to Step 22 .
NO -
  1. Turn the ignition switch OFF.
  1. Disconnect the jumper wire from the A/C condenser fan.
Is the relay OK?
YES -
Go to Step 25 .
NO -
Replace the fan control relay .■
  1. Turn the ignition switch ON (II).
  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 27 .
NO -
Repair open in the wire between the A/C condenser fan and the fan control relay.■
  1. Turn the ignition switch OFF.
  1. Disconnect the jumper wire from ECM connector No. 2.
  1. Disconnect the radiator fan 2P connector.
  1. Check for continuity between the fan control relay 5P socket terminal No. 4 and the radiator 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 radiator fan.■
  1. Check for continuity between the radiator fan 2P connector terminal No. 1 and body ground.
Is there continuity?
YES -
NO -