PINPOINT TEST H : The Rear Heating Ventilation Air Conditioning (RHVAC) Module Does Not Respond To The Diagnostic Scan Tool

WARNING: This page is about a different car, the 2016 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery, Mounting and Cables .

H1 CHECK THE RHVAC MODULE VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

Disconnect: RHVAC module C3198 .

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3198-6	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts?

Yes	GO to H2.
No	VERIFY the BCM fuse 6 (5A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the OEM Electrical Wiring Diagram Introduction to identify the possible causes of the circuit short.

H2 CHECK THE RHVAC MODULE GROUND CIRCUIT FOR AN OPEN

Ignition OFF.

Disconnect: Negative Battery Cable.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3198-5	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes	CONNECT the negative battery cable. GO to H3.
No	REPAIR the circuit.

H3 CHECK THE MS-CAN CIRCUITS BETWEEN THE RHVAC MODULE AND THE DLC FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3198-1	Courtesy of FORD MOTOR COMPANY	C251-3
C3198-2	Courtesy of FORD MOTOR COMPANY	C251-11

Are the resistances less than 3 ohms?

Yes	GO to H4.
No	REPAIR the circuit in question.

H4 CHECK FOR CORRECT RHVAC MODULE OPERATION

Ignition OFF.

Disconnect and inspect the RHVAC module connector and related in-line connectors.

Repair:
- corrosion (replace connector or terminals - clean module pins)
- damaged or bent pins - replace terminals/pins
- pushed-out pins - replace pins as necessary

Reconnect the RHVAC module connector and related in-line connectors. Make sure they seat and latch correctly.

Operate the system and verify the concern is still present.

Is the concern still present?

Yes	CHECK OASIS for any applicable TSBs. If a TSB exists for this concern, discontinue this test and follow TSB instructions. If no TSBs address this concern, INSTALL a new RHVAC module. REFER to Climate Control .
No	The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector.