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Chart C-12A, 3.8L (1 Of 5), Cooling Fan CKT Diagnosis: Notes

PCM uses 3 relays to control 2 cooling fans. Both fans run at low speed when PCM energizes cooling fan relay "G" through PCM terminal GC4 when coolant temperature exceeds 214°F (101°C) or when A/C high side refrigerant temperature exceeds 122°F (50°C). Both fans run at high speed when PCM energizes all 3 relays with coolant temperature exceeding 226°F (108°C) or when A/C high side refrigerant temperature exceeds 149°F (65°C).

NOTE: Test numbers refer to test numbers on diagnostic charts.
  1. Codes 14 or 15 could mean coolant system or coolant temperature sensor operation is not normal so fan(s) operation cannot be checked correctly.
  2. Selecting output tests, Fan 1 with Tech 1 scan tester grounds fan relay "G" through PCM. Fans should cycle on and run at low speed.
  3. Selecting output tests, Fan 2 should cause PCM to energize fan relays "G", "C", and "D". Both fans should run at high speed.
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