Operation CHARM: Car repair manuals for everyone.
Home >> Ford Truck >> 2010 >> Transit Connect L4-2.0L >> Repair and Diagnosis >> Heating and Air Conditioning >> Testing and Inspection >> Pinpoint Tests >> Pinpoint Test J: The Air Conditioning (A/C) Is Always On - A/C Mode Always Commanded ON

Pinpoint Test J: The Air Conditioning (A/C) Is Always On - A/C Mode Always Commanded ON




Climate Control System

Pinpoint Tests

Pinpoint Test J: The Air Conditioning (A/C) is Always On - A/C Mode Always Commanded ON

Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. Diagrams By Number

Normal Operation

Under normal operation, when A/C is requested, the A/C is grounded. When the A/C switch is pressed, a ground is provided to the Instrument Cluster (IC) A/C switch input. When the IC receives this ground, it sends an A/C request message through the High Speed Controller Area Network (HS-CAN) bus to the PCM and an A/C request message through the Medium Speed Controller Area Network (MS-CAN) to the Generic Electronic Module (GEM).

When the GEM receives the A/C request message from the IC, it provides a ground for the A/C switch indicator. Voltage is provided to the indicator. When the GEM provides ground, the indicator illuminates.

- DTC B1262 (Servo Motor Defrost Circuit Failure) - The DTC sets when the GEM detects a continuous ground on the DEFROST mode switch input from the function selector switch to the GEM, indicating a direct short to ground on the circuit.
- DTC P2175 (A/C Request Signal Circuit Short to Ground) - The DTC sets when the IC detects a continuous ground on the A/C switch input to the IC, indicating a direct short to ground on the circuit.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- A/C switch
- Function selector switch
- GEM
- IC
- PCM



PINPOINT TEST J: THE AIR CONDITIONING (A/C) IS ALWAYS ON - A/C MODE ALWAYS COMMANDED ON

NOTE: Before carrying out the following test, diagnose any PCM, GEM or IC DTCs.

NOTE: Before carrying out the following test, check that the A/C system pressure is above 290 kPa (42 psi). If the pressure is below 290 kPa (42 psi), refer to Fluorescent Dye Leak Detection Fluorescent Dye Leak Detection.

-------------------------------------------------
J1 CHECK A/C INDICATOR OPERATION


- Start the engine.
- With the engine running, place the function selector switch to the PANEL position.
- Place the blower motor switch to lowest position.
- Press the A/C switch multiple times.
- Does the A/C indicator turn ON and OFF?

Yes
GO to J5.

No
GO to J2.

-------------------------------------------------
J2 CHECK THE DEFROST GEM PID


- Enter the following diagnostic mode on the scan tool: DEFROST GEM PID .
- With the engine running, place the function selector switch to the PANEL position.
- Does the DEFROST GEM PID read INACTIVE?

Yes
GO to J11.

No
GO to J3.

-------------------------------------------------
J3 CHECK THE DEFROST GEM PID WITH THE FUNCTION SELECTOR SWITCH DISCONNECTED


- Ignition OFF.
- Disconnect: Function Selector Switch C294 .
- Start the engine.
- Enter the following diagnostic mode on the scan tool: DEFROST GEM PID .
- Observe the DEFROST GEM PID.
- Does the DEFROST GEM PID read INACTIVE?

Yes
INSTALL a new function selector switch. TEST the system for normal operation.

No
GO to J4.

-------------------------------------------------
J4 CHECK CIRCUIT 91S-FA20 (BK/YE) FOR A SHORT TO GROUND


- Ignition OFF.
- Disconnect: GEM C201C .
- Measure the resistance between function selector switch C294-3, circuit 91S-FA20 (BK/YE), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to J9.

No
REPAIR circuit 91S-FA20 (BK/YE) for a short to ground. TEST the system for normal operation.

-------------------------------------------------
J5 CHECK AC_SW IC PID WITH THE A/C OFF


- Enter the following diagnostic mode on the scan tool: AC_SW IC PID .
- Press the A/C switch until the A/C indicator is OFF.
- Does the AC_SW IC PID read NO?

Yes
GO to J8.

No
GO to J6.

-------------------------------------------------
J6 CHECK AC_SW IC PID WITH THE A/C SWITCH DISCONNECTED


- Ignition OFF.
- Disconnect: A/C Switch C2891 .
- Start the engine.
- Enter the following diagnostic mode on the scan tool: AC_SW IC PID .
- Observe the AC_SW IC PID.
- Does the AC_SW IC PID read NO?

Yes
INSTALL a new A/C switch. TEST the system for normal operation.

No
GO to J7.

-------------------------------------------------
J7 CHECK CIRCUIT 15S-FA13 (GN/RD) FOR A SHORT TO GROUND


- Ignition OFF.
- Disconnect: IC C220A .
- Measure the resistance between A/C switch C2891-6, circuit 15S-FA13 (GN/RD), harness side and ground.




- Is the resistance greater than 10,000 ohms?

Yes
GO to J10.

No
REPAIR circuit 15S-FA13 (GN/RD) for a short to ground. TEST the system for normal operation.

-------------------------------------------------
J8 CHECK CIRCUIT 91S-FA9 (BK/GN) FOR A SHORT TO VOLTAGE


- Ignition OFF.
- Disconnect: A/C Switch C2891 .
- Disconnect: GEM C201C .
- Ignition ON.
- Measure the voltage between A/C switch C2891-5, circuit 91S-FA9 (BK/GN), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
REPAIR circuit 91S-FA9 (BK/GN) for a short to voltage. TEST the system for normal operation.

No
GO to J9.

-------------------------------------------------
J9 CHECK THE GEM CONNECTION


- Clear the DTCs.
- Disconnect all the GEM connectors.
- Check for:
- corrosion.
- pushed-out pins.
- incorrectly seated connector.
- Connect and correctly seat all the GEM connectors.
- Operate the system.
- Does the concern return?

Yes
INSTALL a new GEM. REFER to Body Control Systems. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

-------------------------------------------------
J10 CHECK THE IC CONNECTION


- Clear the DTCs.
- Disconnect all the IC connectors.
- Check for:
- corrosion.
- pushed-out pins.
- incorrectly seated connector.
- Connect and correctly seat all the IC connectors.
- Operate the system.
- Does the concern return?

Yes
INSTALL a new IC. REFER to Instrument Panel, Gauges and Warning Indicators. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

-------------------------------------------------
J11 CHECK THE PCM CONNECTION


- Clear the DTCs.
- Disconnect all the PCM connectors.
- Check for:
- corrosion.
- pushed-out pins.
- incorrectly seated connector.
- Connect and correctly seat all the PCM connectors.
- Operate the system.
- Does the concern return?

Yes
INSTALL a new PCM. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

-------------------------------------------------

pro multis · About Operation CHARM