Pinpoint Test V: The HVAC Module Does Not Respond To The Scan Tool

WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: 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, MOUNTING AND CABLES .

V1 CHECK THE HVAC VOLTAGE SUPPLY CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: HVAC Module C2357a (Manual A/C).
- Disconnect: HVAC Module C2356a (Dual Automatic Temperature Control (DATC)).
- Ignition ON.
- Measure the voltage between the HVAC module C2357a-13 (manual), C228a-13 or C2356a-13 (DATC), circuit SBP15 (WH/RD), harness side and ground.
  
  Fig 1: Checking HVAC Voltage Supply Circuits For An Open
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to V2.
- No : VERIFY Smart Junction Box (SJB) fuse 15 (10A) is OK. If OK, REPAIR the circuit in question. CLEAR the DTCs. REPEAT the network test with the scan tool. If not OK, REFER to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short.
V2 CHECK THE HVAC GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the HVAC module C2357a-23 (manual), C228a-23 or C2356a-23 (DATC), circuit GD116 (BK/VT), harness side and ground.
  
  Fig 2: Checking HVAC Ground Circuit For An Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to V3.
- No : REPAIR the circuit. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
V3 CHECK THE MS-CAN CIRCUITS BETWEEN THE HVAC MODULE AND THE DLC FOR AN OPEN
- Measure the resistance between the HVAC module C2357a-25 (manual), C228a-25 or C2356a-25 (DATC), circuit VDB06 (GY/OG), harness side and the Data Link Connector (DLC) C251-3, circuit VDB06 (GY/OG), harness side.
  
  Fig 3: Checking MS-CAN Circuits Between HVAC Module And DLC For An Open (1 Of 2)
  Courtesy of FORD MOTOR CO.
- Measure the resistance between the HVAC module C2357a-26 (manual), C228a-26 or C2356a-26 (DATC), circuit VDB07 (VT/OG), harness side and the DLC C251-11, circuit VDB07 (VT/OG), harness side.
  
  Fig 4: Checking MS-CAN Circuits Between HVAC Module And DLC For An Open (2 Of 2)
  Courtesy of FORD MOTOR CO.
- Are the resistances less than 5 ohms?
- Yes : CONNECT the negative battery cable. GO to V4.
- No : REPAIR the circuit as necessary. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
V4 CHECK FOR CORRECT HVAC MODULE OPERATION

Disconnect all the HVAC module connectors.
Check for:
- corrosion
- damaged pins
- pushed-out pins
Connect all the HVAC module connectors and make sure they seat correctly.
Operate the system and verify the concern is still present.
Is the concern still present?

Yes : INSTALL a new HVAC module. REFER to CLIMATE CONTROL . CLEAR the DTCs. REPEAT the network test with the scan tool.
No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the network test with the scan tool.