Explorer 4WD V6-4.0L (2009)
Communications Network
Pinpoint Tests
Pinpoint Test I: The HVAC Module Does Not Respond To The Scan Tool
Refer to Wiring Diagram Set 14, Module Communications Network for schematic and connector information. See: Diagrams/Electrical
Diagrams/Diagrams By Number
Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. See: Diagrams/Electrical
Diagrams/Diagrams By Number
Normal Operation
The HVAC module communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN). Circuits VDB06 (GY/OG)
(MS-CAN +) and VDB07 (VT/OG) (MS-CAN -) provide the network connection to the HVAC module. Voltage for the HVAC module is provided by
circuits CBP20 (YE/VT) and SBP28 (GN/RD). Circuit GD145 (BK/BU) provides ground.
This pinpoint test is intended to diagnose the following:
-
Fuse
-
Wiring, terminals or connectors
-
HVAC module
PINPOINT TEST I: THE HVAC MODULE DOES NOT RESPOND TO THE SCAN TOOL
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the
connector.
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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I1 CHECK THE HVAC MODULE VOLTAGE SUPPLY CIRCUITS FOR AN OPEN
-
Ignition OFF.
-
Disconnect: HVAC Module C228a.
-
Ignition ON.
-
Measure the voltage between the HVAC module C228a-13, circuit SBP28 (GN/RD), and between the HVAC module C228a-3, circuit CBP20
(YE/VT) and ground.
-
Are the voltages greater than 10 volts?
Yes
GO to I2.
No
VERIFY the Smart Junction Box (SJB) fuse 20 (10A) or fuse 28 (10A) is OK. If OK, REPAIR the circuit in question. CLEAR the DTCs. If not OK,
REFER to the Wiring Diagrams to identify the possible causes of the circuit short. REPEAT the network test with the scan tool.
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I2 CHECK THE HVAC GROUND CIRCUIT FOR AN OPEN
-
Ignition OFF.
-
Disconnect: Negative Battery Cable.