Diagnostic Test

1) DTC IS ACTIVE
Start the engine and allow it to idle for at least 60 seconds.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

With a scan tool, select View DTCs.

Is the status Active for this DTC?

Yes
1. Go to 2).
No
1. Refer to *CHECKING FOR AN INTERMITTENT DTC .
2) LEFT SPEED CONTROL SWITCH
Turn the ignition off.

Disconnect the Left Speed Control Switch harness connector.

Turn the ignition on.

With the scan tool, read the (V37) S/C Signal 1 input voltage.

NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus.1 volt) with the connector disconnected.

Is the voltage on the scan tool displayed as described above?

Yes
1. Replace the Left Speed Control Switch in accordance with the Service Information.
2. Perform PCM VERIFICATION TEST .
No
1. Go to 3).
3) RIGHT SPEED CONTROL SWITCH
Turn the ignition off.

Disconnect the Right Speed Control Switch harness connector.

Turn the ignition on.

With the scan tool, read the (V37) S/C Signal 1 input voltage.

NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus.1 volt) with the connector disconnected.

Is the voltage on the scan tool displayed as described above?

Yes
1. Replace the Right Speed Control Switch in accordance with the Service Information.
2. Perform PCM VERIFICATION TEST .
No
1. Go to 4).
4) (V37) S/C SIGNAL 1 CIRCUIT SHORTED TO GROUND

Fig 1: Measuring The Resistance Between Ground And The S/C Signal 1 Circuit
Courtesy of CHRYSLER LLC

Turn the ignition off.

Measure the resistance between ground and the (V37) S/C Signal 1 circuit.

Is the resistance above 100 ohms?

Yes
1. Go to 5).
No
1. Repair the (V37) S/C Signal 1 circuit for a short to ground.
2. Perform PCM VERIFICATION TEST .
5) (V37) S/C SIGNAL 1 CIRCUIT SHORTED TO THE (K975) S/C SWITCH GROUND CIRCUIT

Fig 2: Measuring The Resistance Between The S/C Signal 1 Circuit And The S/C Switch Ground Circuit
Courtesy of CHRYSLER LLC

Measure the resistance between the (V37) S/C Signal 1 circuit and the (K975) S/C Switch Ground circuit.

Is the resistance above 100 ohms?

Yes
1. Go to 6).
No
1. Repair the (V37) S/C Signal 1 circuit for a short to the (K975) S/C Switch Ground circuit.
2. Perform PCM VERIFICATION TEST .
6) (V37) S/C SIGNAL 1 CIRCUIT OPEN OR HIGH RESISTANCE

Fig 3: Measuring The Resistance Of The S/C Signal 1 Circuit Between The Speed Control Switch Harness Connectors And The Appropriate Terminal Of Special Tool #8815
Courtesy of CHRYSLER LLC

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (V37) S/C Signal 1 circuit between the Left Speed Control Switch harness connector and the appropriate terminal of special tool #8815 and between the Right Speed Control Switch harness connector and the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes
1. Go to 7).
No
1. Repair the (V37) S/C Signal 1 circuit for an open circuit or high resistance.
2. Perform PCM VERIFICATION TEST .
7) POWERTRAIN CONTROL MODULE (PCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Left Speed Control Switch and the Powertrain Control Module (PCM) and the Right Speed Control Switch and the Powertrain Control Module (PCM).

Look for any chafed, pierced, pinched, or partially broken wires.

Look for broken, bent, pushed out or corroded terminals.

Refer to any Technical Service Bulletins that may apply.

Were any problems found?

Yes
1. Repair as necessary.
2. Perform PCM VERIFICATION TEST .
No
1. Replace the Powertrain Control Module (PCM) in accordance with the Service Information.
2. Perform PCM VERIFICATION TEST .