Ford 2001 Ranger, Manual

Page: 309 / 1218

412-02-15 412-02-15 Heating and Ventilation
DIAGNOSIS AND TESTING (Continued)
PINPOINT TEST F: DTC C1779 BLOWER SWITCH FAILURE
TEST STEP ACTION TO TAKE
•
With key OFF, measure the resistance between BOB pins 60, 61, 62 and Yes = GO to F6.
ground (BOB pin 80).
•
Are the resistances greater than 10,000 ohms?
No = REPAIR the wire(s) in
question.
F6 CHECK CIRCUITS 751 (DB/W), 752 (Y/R), AND 754 (LG/W) FOR
SHORT(S) TO POWER
•
With key ON, measure the voltage between BOB pins 60, 61, 62 and Yes = REPAIR the wire(s) in
ground (BOB pin 80). question.
•
Are any of the voltages greater than 0 volts?
No = REPLACE the IAA module.
REFER to Section 412-04 .
F7 CHECK BLOWER SWITCH
•
With key OFF, disconnect blower switch C232 and check the continuity Yes = REPLACE the IAA module.
of the blower switch by measuring the resistance between the circuit 57 REFER to Section 412-04 .
(BK wire) terminal and the indicated terminals on the blower switch.
Compare the readings to the values below:
Low Blower Position
No = REPLACE the blower
switch.
— Circuit 751 (DB/W wire) terminal = Open
— Circuit 752 (Y/R wire) terminal = Open
— Circuit 754 (LG/W wire) terminal = Open
Medium Blower Position
— Circuit 751 (DB/W wire) terminal = Closed
— Circuit 752 (Y/R wire) terminal = Open
— Circuit 754 (LG/W wire) terminal = Open
Medium-High Blower Position
— Circuit 751 (DB/W wire) terminal = Closed
— Circuit 752 (Y/R wire) terminal = Closed
— Circuit 754 (LG/W wire) terminal = Open
High Blower Position
— Circuit 751 (DB/W wire) terminal = Open
— Circuit 752 (Y/R wire) terminal = Closed
— Circuit 754 (LG/W wire) terminal = Closed
•
Is the blower switch OK?
PINPOINT TEST G: DTC C1780 TEMPERATURE SELECT FAILURE
TEST STEP ACTION TO TAKE
G1 CHECK TEMPERATURE CONTROL OPERATION
•
With key ON, monitor the interface adapter assembly (IAA) module PID Yes = System OK. CHECK wiring
SET TMP while rotating the temperature control knob from the full for intermittent connections.
cool position to the full warm position.
•
Does the SET TMP PID indicate approximately 98% at the full
No = GO to G2.
cool position and approximately 1% at the full warm position?
G2 CHECK TEMPERATURE CONTROL VOLTAGE REFERENCE
•
With key OFF, disconnect temperature control C231. Yes = GO to G5.
•
With key ON, measure the voltage between the LG/O wire and Y/LG No = GO to G3.
wire on temperature control C231.
•
Is the voltage between 4.8 and 5.2 volts?
G3 CHECK CIRCUITS 3057 (LG/O) AND 3059 (Y/LG) FOR OPEN(S)
•
Connect 104-Pin Breakout Box (BOB) to IAA module C1945; leave IAA Yes = GO to G4.
module disconnected.
(Continued)
2001 Ranger EV, 01/2001