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Ford Ranger EV (2001 year). Manual - part 77

412-02-13

Heating and Ventilation

DIAGNOSIS AND TESTING (Continued)

PINPOINT TEST E: DTC C1776 HEATER SYSTEM FAILURE

TEST STEP

ACTION TO TAKE

E9 CHECK PTC HEATER CORE B CONTROL CIRCUIT FOR

SHORT TO GROUND

•

With key OFF, disconnect BOB from IAA module; leave BOB

Yes =

GO to E10.

connected to IAA module C1945.

•

With key OFF, measure the resistance between BOB pin 34 and ground

No =

REPLACE the IAA module.

(BOB pin 80).

REFER to

Section 412-04

•

Is the resistance less than 7,000 ohms?

E10 CHECK CIRCUIT 3261 (PK/Y) FOR SHORT TO GROUND

•

Reconnect the 12-volt auxiliary battery negative cable.

Yes =

REPLACE the PTC

switching module. REFER

Section 412-04

•

With key OFF, disconnect PTC switching module C1999 and measure

No =

REPAIR the PK/Y wire.

the resistance between BOB pin 34 and ground (BOB pin 80).

•

Is the resistance greater than 10,000 ohms?

E11 CHECK PTC HEATER CORES

•

Disconnect the 12-volt auxiliary battery negative cable.

Yes =

GO to E12.

•

Remove the high-voltage power distribution box (HVPDB) cover.

No =

REPLACE the PTC heater

•

Disconnect PTC switching module high-voltage C1912 and measure the

core.

resistance between the DB wire and DG wire on PTC switching module

C1912M.

•

Measure the resistance between the R wire and W wire on PTC

switching module C1912M.

•

Are the resistances between 65 and 140 ohms?

E12 CHECK HIGH-VOLTAGE POWER TO PTC SWITCHING

MODULE

Yes =

GO to E17.

WARNING: The following test steps contain high-voltage

procedures. High-voltage insulated safety gloves and face shield must

be worn when carrying out the following steps. Failure to follow this

warning may result in severe personal injury or death.

•

Disconnect HVPDB PTC switching module high-voltage C1920.

•

Reinstall the HVPDB cover.

No =

GO to E13.

•

Reconnect the 12-volt auxiliary battery negative cable.

•

With key ON, measure the voltage between circuit 3104 (DB wire) and

circuit 3105 (W wire) on HVPDB PTC switching module C1920F.

•

Is the voltage greater than 300 volts?

E13 CHECK HIGH-VOLTAGE FUSE

•

With key OFF, disconnect the 12-volt auxiliary battery negative cable.

Yes =

REPLACE the 25A PTC

HTR fuse. GO to E14.

•

Disconnect high-voltage auxiliary load in-line C1935 on the traction

No =

REPLACE the HVPDB.

battery support tray.

REFER to

Section 414-03A

•

Disconnect all HVPDB high-voltage connectors.

Section 414-03B

•

Disconnect power steering assembly high-voltage C1895.

•

Measure the resistance of the 25A PTC HTR fuse.

•

Is the resistance greater than 1,000 ohms?

E14 CHECK PTC SWITCHING MODULE FOR SHORT

•

Measure the resistance between circuit 3104 (DB wire) and circuit 3105

Yes =

REPLACE the PTC

(W wire) on HVPDB PTC switching module C1920M.

switching module.

•

Is the resistance less than 30 ohms?

No =

GO to E15.

E15 CHECK HVPDB FOR SHORT

•

Measure the resistance between circuit 3104 (DB wire) and circuit 3105

Yes =

GO to E16.

(W wire) on HVPDB PTC switching module C1920F.

(Continued)

412-02-14

Heating and Ventilation

DIAGNOSIS AND TESTING (Continued)

PINPOINT TEST E: DTC C1776 HEATER SYSTEM FAILURE

TEST STEP

ACTION TO TAKE

•

Is the resistance greater than 10,000 ohms?

No =

REPLACE the HVPDB.

REFER to

Section 414-03A

Section 414-03B

E16 CHECK SYSTEM

•

With key OFF, reconnect all component connectors that were

Yes =

REPLACE the PTC

disconnected.

switching module.

REPLACE the 25A PTC

HTR fuse. REFER to

Section 414-03A

Section 414-03B

•

With key ON, set the mode select knob to the PANEL/FLOOR position,

No =

System OK.

the temperature control knob to the full warm position, and the blower

control knob to the HIGH speed position.

•

Does the 25A PTC HTR high-voltage fuse fail again?

E17 INSPECT PTC HEATER CORES

•

Remove the PTC heater core and check for contaminants (excessive

Yes =

REPLACE the PTC

moisture or debris) on the heater core.

switching module.

•

Is the heater core clear of contaminants?

No =

REMOVE the contaminants.

If necessary, REPLACE the

PTC heater core.

PINPOINT TEST F: DTC C1779 BLOWER SWITCH FAILURE

TEST STEP

ACTION TO TAKE

F1 CHECK BLOWER SWITCH STATUS

•

With key ON, monitor the interface adapter assembly (IAA) module PID

Yes =

System OK. CHECK wiring

BLOWER while rotating the blower control knob through all the blower

for intermittent connections.

speed positions.

•

Does the BLOWER PID agree with all the blower speed positions?

No =

GO to F2.

F2 CHECK BLOWER SWITCH INPUT VOLTAGE REFERENCES

•

Connect 104-Pin Breakout Box (BOB) to IAA module and IAA module

Yes =

GO to F7.

C1945.

•

With key ON, measure the voltage between BOB pins 60, 61, 62 and

No =

GO to F3.

ground (BOB pin 80).

•

Do the voltages fluctuate between 0 and 2.8 volts?

F3 CHECK GROUND TO BLOWER SWITCH

•

With key OFF, disconnect blower switch C232 and measure the

Yes =

GO to F4.

resistance between the BK wire on blower switch C232 and ground.

•

Is the resistance less than 5 ohms?

No =

REPAIR the BK wire.

F4 CHECK CIRCUITS 751 (DB/W), 752 (Y/R), AND 754 (LG/W) FOR

OPEN(S)

•

With key OFF, disconnect IAA module from BOB; leave BOB

Yes =

GO to F5.

connected to IAA module C1945.

•

With key OFF, measure the resistance of the DB/W wire between blower No =

REPAIR the wire(s) in

switch C232 and BOB pin 62.

question.

•

With key OFF, measure the resistance of the Y/R wire between blower

switch C232 and BOB pin 61.

•

With key OFF, measure the resistance of the LG/W wire between blower

switch C232 and BOB pin 60.

•

Are the resistances less than 5 ohms?

F5 CHECK CIRCUITS 751 (DB/W), 752 (Y/R), AND 754 (LG/W) FOR

SHORT(S) TO GROUND

(Continued)

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)

412-02-16

Heating and Ventilation

DIAGNOSIS AND TESTING (Continued)

PINPOINT TEST G: DTC C1780 TEMPERATURE SELECT FAILURE

TEST STEP

ACTION TO TAKE

•

With key OFF, measure the resistance of the LG/O wire between

No =

REPAIR the wire(s) in

temperature control C231 and BOB pin 84.

question.

•

With key OFF, measure the resistance of the Y/LG wire between

temperature control C231 and BOB pin 71.

•

Are the resistances less than 5 ohms?

G4 CHECK CIRCUIT 3057 (LG/O) FOR SHORT TO GROUND

•

With key OFF, measure the resistance between BOB pin 84 and ground

Yes =

REPLACE the IAA module.

(BOB pin 80).

REFER to

Section 412-04

•

Is the resistance greater than 10,000 ohms?

No =

REPAIR the LG/O wire.

G5 CHECK CIRCUIT 3058 (LG/R) FOR OPEN

•

Connect 104-Pin Breakout Box (BOB) to IAA module C1945; leave IAA Yes =

GO to G6.

module disconnected.

•

With key OFF, measure the resistance of the LG/R wire between pin 2

No =

REPAIR the LG/R wire.

on temperature control C231 and BOB pin 50.

•

Is the resistance less than 5 ohms?

G6 CHECK CIRCUIT 3058 (LG/R) FOR SHORT TO GROUND

•

With key OFF, measure the resistance between BOB pin 50 and ground

Yes =

GO to G7.

(BOB pin 80).

•

Is the resistance greater than 10,000 ohms?

No =

REPAIR the LG/R wire.

G7 CHECK CIRCUIT 3058 (LG/R) FOR SHORT TO POWER

•

With key ON, measure the voltage between BOB pin 50 and ground

Yes =

REPAIR the LG/R wire.

(BOB pin 80).

•

Is the voltage greater than 0 volts?

No =

GO to G8.

G8 CHECK RESISTANCE OF TEMPERATURE CONTROL

POTENTIOMETER

•

With key OFF, reconnect temperature control C231.

Yes =

REPLACE the IAA module.

REFER to

Section 412-04

•

With key OFF, measure the resistance between the BOB pins 50 and 84

No =

REPLACE the temperature

with the temperature control knob in the indicated positions and verify

control potentiometer.

the resistances below:

— Full cool = 90-300 ohms
— Midscale = 2,000-3,000 ohms
— Full warm = 4,000-5,000 ohms

•

Are the resistances OK?

PINPOINT TEST H: DTC B1857 CLIMATE CONTROL ON/OFF SWITCH FAILURE

TEST STEP

ACTION TO TAKE

H1 IDENTIFY VACUUM PUMP SYMPTOM

•

With key ON, set the mode select knob to the OFF and PANEL/FLOOR Yes = GO to

Pinpoint Test Q.

positions and listen for the vacuum pump cycling on and off

continuously.

•

Does the vacuum pump cycle on and off continuously?

No =

GO to H2.

H2 IDENTIFY VEHICLE OPTION

•

Identify the vehicle option (A/C or non-A/C).

Yes =

GO to H3.

•

Is the vehicle equipped with A/C?

No =

GO to H4.

H3 CARRY OUT ON-DEMAND SELF-TEST IN A/C MODE

•

With key ON, set the mode select knob to the A/C position and carry out Yes =

GO to H5.

the on-demand self-test for the interface adapter assembly (IAA) module.

•

Does DTC B1857 Climate Control On/Off Switch Failure occur?

No =

GO to H4.

(Continued)

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