Component Diagnostic Charts - PFI

Fig. 019 - Chart C-12 Coolant Fan Control Circuit with A/C (1 of 2):

Fig. 020 - WIRING DIAGRAM for Chart C-12 Coolant Fan Control Circuit with A/C (1 of 2). VIN J:

CHART C-12

FAN CONTROL CIRCUIT

1.8L TURBO "J" SERIES

Battery voltage, CKT 2, is supplied to the fan control relay terminal "D" or "E" and to the delay relay terminal "7".
Ignition voltage, CKT 250, is supplied to the fan control relay terminal "C" and to the delay relay terminal "5".
Grounding control relay terminal "B", CKT 335, will close the fan control relay and supply battery voltage to the fan motor.
If the ignition switch is turned "OFF" and the fan temperature switch is closed, the fan delay relay will continue to supply battery voltage to the cooling fan circuit 903 and the low speed resistor. The fan will run on low speed for about 5 minutes if the temperature switch remains closed and the ignition "OFF".
A. ECM Control
a. A/C "ON".
b. Vehicle speed less than 35 MPH.
c. CKT 335 and 409 to relay terminal "B" grounded by ECM at terminal C1.
d. Coolant temperature less than 110°C
B. After-Run Delay Relay Control
a. Ignition "OFF".
b. Coolant temperature above 110°C.
c. Fan temperature switch closed grounding CKT 904.
d. Delay relay closed supplying battery voltage to CKT 903.
C. Coolant Temperature Control
a. Coolant above 110°C.
b. Temperature switch closed grounding CKT 904 and timer delay terminal "3".
c. Ignition "ON".
d. Delay relay module terminal "6" grounding CKT 335 to control relay terminal "B".
1. Checks for the fan delay relay sticking "ON" causing a low battery condition.
2. Checks fan motor, time delay relay, CKT 335 and 904.
3. The delay relay supplies a current limited 12 volts to terminal "1". The ignition switch will ground terminal "1" in crank position. Making the test with auto transmission in "Drive" or manual with clutch released will prevent starter engagement during the test.
If the ignition switch is "OFF" the relay should allow the fan to run low speed for about 5 minutes. This would be the time to check the timer feature if it is considered part of the problem.

Fig. 020 - WIRING DIAGRAM for Chart C-12 Coolant Fan Control Circuit with A/C (1 of 2). VIN J:

Fig. 021 - Chart C-12 Coolant Fan Control Circuit with A/C. (2 of 2) VIN J:

CHART C-12 (2 OF 2)

FAN CONTROL CIRCUIT

1.8L TURBO "J" SERIES

FUEL INJECTION (PORT)

4. Solenoids and relays are turned "ON" or "OFF" by the ECM internal electronic switches called "drivers". Each driver is part of a group of four called "Quad-Drivers". Failure of one can damage any other driver within the set.
Solenoid or relay coil resistance must measure more than 20 ohms. Less resistance will cause early failure of the ECM "DRIVER". Using an ohmmeter, check the coil resistance of the following before installing a replacement ECM.
a. Fan control relay - pin opposite harness terminals "B" and "C"
b. A/C clutch control relay pins opposite harness terminals "A" and "C".
c. TCC solenoid