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Home >> Cadillac >> 1997 >> Catera >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests 3.0L >> Circuit Diagnosis Tests >> Engine Cooling Fan Does Not Operate

Engine Cooling Fan Does Not Operate

  1. Locate test connector within the Engine Control Module (ECM) housing. Using a fused jumper wire, connect terminal No. 4 (Brown/White wire) of test connector to a known good ground. If engine cooling fan comes on, go to next step. If engine cooling fan does not come on, go to step 3).
  2. Check for open or high resistance if Brown/White wire or Black (ground) wire to temperature switch No. 1. Repair if necessary. If wires are okay, replace temperature switch No. 1. After repairs, reconnect wiring and components. Verify engine cooling fan operates properly.
  3. Disconnect fan control relay (K67). Using a DVOM, measure resistance between terminal No. 4 of test connector and Brown/White wire terminal of fan control relay. If resistance is less than 2 ohms, go to step 5). If resistance is not as specified, go to next step.
  4. Repair open circuit or high resistance in Brown/White wire between fan control relay and test connector. After repairing wire, reconnect wiring and components. Verify engine cooling fan operates properly.
  5. Using a DVOM, measure voltage between ground and terminal No. 2 (Red wire) to fan control relay (K67). If battery voltage is present, go to step 7). If battery voltage is not present, go to next step.
  6. Repair open circuit or high resistance in Red wire to fan control relay. After repairing wire, reconnect wiring and components. Verify engine cooling fan operates properly.
  7. Measure voltage between ground and terminal No. 4 (Red wire) at fan control relay (K67). If battery voltage is present, go to step 9). If battery voltage is not present, go to next step.
  8. Check fuse No. 42 (40-amp). If fuse is okay, repair open circuit or high resistance in Red wire between fan control relay and fuse. Also check Red wire circuit to battery. After repairs, reconnect wiring and components. Verify engine cooling fan operates properly.
  9. Connect a fused jumper wire between terminal No. 4 (Red wire) and Red/White wire terminal of fan control relay (K67) wiring harness connector. If cooling fan comes on, go to next step. If cooling fan does not come on, go to step 11).
  10. Replace fan control relay (K67). After replacing relay, reconnect wiring and components. Verify engine cooling fan operates properly.
  11. Disconnect engine cooling fan. Measure voltage between ground and Red/White wire terminal of cooling fan wiring harness connector. If battery voltage is present, go to step 13). If battery voltage is not present, go to next step.
  12. Repair open circuit, high resistance, or short to ground in Red/White wire between fan control relay and cooling fan. After repairing wire, reconnect wiring and components. Verify engine cooling fan operates properly.
  13. Measure resistance between ground and Black wire terminal of cooling fan wiring harness connector. If resistance is less than 2 ohms, go to step 15). If resistance is not as specified, go to next step.
  14. Repair open circuit or high resistance in Black (ground) wire to cooling fan. After repairing wire, reconnect wiring and components. Verify engine cooling fan operates properly.
  15. Replace engine cooling fan. After replacing fan, reconnect wiring and components. Verify engine cooling fan operates properly.
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