Ford Electric Ranger 2001 Manual page 306

412-02-12
DIAGNOSIS AND TESTING (Continued)
PINPOINT TEST E: DTC C1776 HEATER SYSTEM FAILURE
• Remove the high-voltage power distribution box (HVPDB) cover.
• Disconnect PTC switching module high-voltage C1912 and measure the
resistance between the DB wire and DG wire on PTC switching module
C1912M.
• Is the resistance between 65 and 140 ohms?
E4 CHECK PTC HEATER CORE A CONTROL SIGNAL
• With key OFF, reconnect PTC switching module C1912.
• Reinstall HVPDB cover.
• Connect 104-Pin Breakout Box (BOB) to IAA module and IAA module
C1945.
• Reconnect the 12-volt auxiliary battery negative cable.
• With key ON, set the mode select knob to the PANEL/FLOOR position
and the temperature control knob to the full warm position, and monitor
IAA module PID CORE A.
• Cycle the ignition key (if necessary) OFF/ON until the CORE A PID
indicates ON.
• Measure the voltage between BOB pin 33 and ground (BOB pin 80).
• Is the voltage greater than 2 volts?
E5 CHECK PTC HEATER CORE A CONTROL CIRCUIT FOR
SHORT TO GROUND
• With key OFF, disconnect BOB from IAA module; leave BOB
connected to IAA module C1945.
• With key OFF, measure the resistance between BOB pin 33 and ground
(BOB pin 80).
• Is the resistance less than 7,000 ohms?
E6 CHECK CIRCUIT 3260 (O/W) FOR SHORT TO GROUND
• Reconnect the 12-volt auxiliary battery negative cable.
• With key OFF, disconnect PTC switching module C1999 and measure
the resistance between BOB pin 33 and ground (BOB pin 80).
• Is the resistance greater than 10,000 ohms?
E7 CHECK PTC HEATER CORE B
• Disconnect the 12-volt auxiliary battery negative cable.
• Remove the high-voltage power distribution box (HVPDB) cover.
• Disconnect PTC switching module high-voltage C1912 and measure the
resistance between the R wire and W wire on PTC switching module
C1912M.
• Is the resistance between 65 and 140 ohms?
E8 CHECK PTC HEATER CORE B CONTROL SIGNAL
• With key OFF, reconnect PTC switching module C1912.
• Reinstall HVPDB cover.
• Connect 104-Pin Breakout Box (BOB) to IAA module and IAA module
C1945.
• Reconnect the 12-volt auxiliary battery negative cable.
• With key ON, set the mode select knob to the PANEL/FLOOR position
and the temperature control knob to the full warm position, and monitor
IAA module PID CORE B.
• Cycle the ignition key (if necessary) OFF/ON until the CORE B PID
indicates ON.
• Measure the voltage between BOB pin 34 and ground (BOB pin 80).
• Is the voltage greater than 2 volts?
(Continued)
Heating and Ventilation
TEST STEP ACTION TO TAKE
No = REPLACE the PTC heater
core.
Yes = GO to E17.
GO to E5.
No =
GO to E6.
Yes =
No = REPLACE the IAA module.
REFER to Section
Yes = REPLACE the PTC
switching module. REFER
to Section 412-04.
No = REPAIR the O/W wire.
GO to E8.
Yes =
No = REPLACE the PTC heater
core.
Yes = GO to E17.
GO to E9.
No =
2001 Ranger EV, 01/2001
412-02-12
412-04.