Ford 2001 Ranger, Manual

Page: 319 / 1218

412-02-25 412-02-25 Heating and Ventilation
DIAGNOSIS AND TESTING (Continued)
PINPOINT TEST P: NO HEAT/INSUFFICIENT HEAT
TEST STEP ACTION TO TAKE
P1 CHECK POSITIVE TEMPERATURE COEFFICIENT (PTC)
HEATER CORE CONTROL SIGNALS
•
Connect 104-Pin Breakout Box (BOB) to interface adapter assembly Yes = GO to P3.
(IAA) module and IAA module C1945.
•
With key ON, set the mode select knob to the PANEL/FLOOR position No = If voltage equals 0 volts,
and the temperature control knob to the full warm position, and monitor REPLACE the IAA module.
IAA module PIDs CORE A and CORE B. REFER to Section 412-04 .
•
Note which PID indicates ON.
•
If CORE A PID indicates ON, measure the voltage between BOB pin If voltage is greater than 4.5
33 and ground (BOB pin 80). volts, GO to P2.
•
If CORE B PID indicates ON, measure the voltage between BOB pin
34 and ground (BOB pin 80).
•
Is the voltage between 2 and 3 volts?
P2 CHECK CIRCUIT 3260 (O/W) FOR OPEN
•
With key OFF, disconnect PTC switching module C1999 and measure Yes = REPLACE the PTC
the resistance of the O/W wire between pin 4 on PTC switching module switching module.
C1999 and BOB pin 33.
•
Is the resistance less than 5 ohms?
No = REPAIR the O/W wire.
P3 CHECK PTC HEATER CORE CONTROL SIGNALS AFTER
CYCLING IGNITION KEY
•
Turn the ignition key to the OFF position and then to the ON position. Yes = System OK. CHECK wiring
for intermittent connections.
•
With key ON, set the mode select knob to the PANEL/FLOOR position No = If voltage equals 0 volts,
and the temperature control knob to the full warm position, and monitor REPLACE the IAA module.
IAA module PIDs CORE A and CORE B. REFER to Section 412-04 .
•
Note which PID indicates ON.
•
If CORE A PID indicates ON, measure the voltage between BOB pin If voltage is greater than 4.5
33 and ground (BOB pin 80). volts, GO to P4.
•
If CORE B PID indicates ON, measure the voltage between BOB pin
34 and ground (BOB pin 80).
•
Is the voltage between 2 and 3 volts?
P4 CHECK CIRCUIT 3261 (PK/Y) FOR OPEN
•
With key OFF, disconnect PTC switching module C1999 and measure Yes = REPLACE the PTC
the resistance of the PK/Y wire between pin 5 on PTC switching module switching module.
C1999 and BOB pin 34.
•
Is the resistance less than 5 ohms?
No = REPAIR the PK/Y wire.
PINPOINT TEST Q: VACUUM PUMP CYCLES ON AND OFF WITHOUT BRAKE PEDAL ACTIVATION
(CLIMATE CONTROL VACUUM SYSTEM LEAK TEST)/INCORRECT AIRFLOW THROUGH CLIMATE
CONTROL OUTLETS
TEST STEP ACTION TO TAKE
Q1 CHECK SYSTEM AIRFLOW
•
With key ON, set the blower control knob to the HIGH position and Yes = System OK. If vacuum
rotate the mode select knob through all mode positions. pump cycles on and off
continuously without brake
pedal activation, GO to Q4.
•
Check the airflow through the climate control outlets for all mode No = If air flows through
positions. defroster outlets for all
•
Does air flow through the correct outlets for all mode positions?
mode positions, GO to Q2.
If air flows through
incorrect outlets, GO to
Q10.
(Continued)
2001 Ranger EV, 01/2001