Pinpoint Test B: All Auxiliary Switch On Indicators Or Controlled Components Are Inoperative Or Always On
WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
- Refer to Customer Access
for schematic and connector information.
Normal Operation and Fault Conditions
The upfitter switch indicators have a unique ground circuit. If an upfitter device operates, but the indicator does not illuminate, then the switch or ground is bad. REFER to: Auxiliary Switches .
Possible Sources
- Wiring, terminals or connectors
- Upfitter (auxiliary) switch assembly
- BCM
- B1 CHECK THE UPFITTER SYSTEM
- Ignition OFF.
- Operate all the upfitter accessories.
Are all the upfitter accessories always ON?
Yes GO to B2 No If some, but not all, auxiliary switch ON indicators are inoperative, INSTALL a new upfitter switch assembly. REFER to: Auxiliary Switches . For all other symptoms, GO to B4 - B2 CHECK THE DEMAND LAMP VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect BCM C2280C.
- Turn any demand (map or vanity mirror) lamp on.
Does the demand lamp turn on?
Yes REPAIR the circuit. No GO to B3 - B3 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION
- Disconnect and inspect all BCM 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 BCM 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 service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new BCM. REFER to: Body Control Module (BCM) . 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. CLEAR the Diagnostic Trouble Codes (DTCs). - B4 CHECK THE UPFITTER SYSTEM
- Ignition ON.
- Operate all the upfitter accessories.
Do the upfitter accessories operate?
Yes GO to B5 No GO to B6 - B5 CHECK THE UPFITTER SWITCH INDICATOR GROUND
- Ignition OFF.
- Disconnect Upfitter switch C9120.
- Measure:
Positive Lead Measurement / Action Negative Lead C9120-6 Ground
Is the resistance less than 3 ohms?
Yes INSTALL a new upfitter switch assembly. REFER to: Auxiliary Switches . No REPAIR the circuit. - B6 CHECK FOR VOLTAGE TO THE UPFITTER SWITCH
- Ignition OFF.
- Disconnect Upfitter switch C9120.
- Ignition ON.
Is the voltages greater than 11 volts?
Yes INSTALL a new upfitter switch assembly. REFER to: Auxiliary Switches . No REPAIR the affected circuit.