Pinpoint Test N : The Rear Heating, Ventilation And Air Conditioning (RHVAC) Module Does Not Respond To The Diagnostic Scan Tool

WARNING: This page is about a different car, the 2018 Lincoln Continental. However, it is still accessible from the selected car via links, so may be relevant.

N1 CHECK THE RHVAC (REAR HEATING, VENTILATION AND AIR CONDITIONING) MODULE VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

Ignition OFF.

Disconnect: RHVAC module C3669 .

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3669-6	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts?

Yes

GO to N2

No	VERIFY the BCM fuse 12 (7.5A) is OK. If OK, REPAIR the circuit. If not OK, REFER to OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify the possible causes of the circuit short.

N2 CHECK THE RHVAC (REAR HEATING, VENTILATION AND AIR CONDITIONING) MODULE GROUND CIRCUIT FOR AN OPEN

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3669-5	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes

GO to N3

No	REPAIR the circuit.

N3 CHECK THE MS-CAN (MEDIUM SPEED-CONTROLLER AREA NETWORK) CIRCUITS BETWEEN THE RHVAC (REAR HEATING, VENTILATION AND AIR CONDITIONING) MODULE AND THE GWM (GATEWAY MODULE A) FOR AN OPEN

Disconnect GWM C2803 .

Measure:

Positive Lead	Measurement / Action	Negative Lead
C3669-1	Courtesy of FORD MOTOR COMPANY	C2803-16
C3669-2	Courtesy of FORD MOTOR COMPANY	C2803-15

Are the resistances less than 3 ohms?

Yes

GO to N4

No	REPAIR the circuit in question.

N4 CHECK FOR CORRECT RHVAC (REAR HEATING, VENTILATION AND AIR CONDITIONING) MODULE OPERATION

Ignition OFF.

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

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

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

Operate the system and determine if the concern is still present.

Is the concern still present?

Yes

CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new RHVAC module. Refer to: Rear Heating, Ventilation and Air Conditioning (RHVAC) Control Module .

No	The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.