CM2150 Electronic Control System – 019-256   Two-Speed Axle Switch Circuit

CAUTION  The leads must fit tightly in the connector without expanding the pins in the connector otherwise the connector will be damaged.

If INSITE™ electronic service tool is available, monitor the 2-speed axle switch circuit for proper operation.

If
not, follow the troubleshooting procedures in this section.

Disconnect the OEM harness from the ECM connector.

Insert a test lead into the 2-speed axle switch signal pin of the OEM harness connector, and attach it to a multimeter probe.

Touch the other multimeter probe to the engine block ground.

Move the 2-speed axle switch to the ON position.

The multimeter
must show a closed circuit (10 ohms or less).

If the circuit is
not closed, inspect the 2-speed-axle-switch signal wire for an open circuit. Refer to the OEM troubleshooting and repair manual.

If the resistance is within specification, the 2-speed axle switch signal pin
must be checked for a short circuit to ground, a short circuit from pin-to-pin, and a short circuit to an external voltage source.

Isolate the 2-speed axle switch circuit.

Insert the test lead attached to the multimeter probe into the 2-speed axle switch signal pin of the OEM harness connector.

Touch the other multimeter probe to the engine block, and measure the resistance.

The multimeter
must show an open circuit (100k ohms or more).

If the circuit is
not open, there is a short circuit to ground in the 2-speed axle switch circuit, provided that the switch has been previously checked.

Repair or replace the wire connected to the 2-speed axle switch signal pin according to the vehicle manufacturer’s instructions.

Isolate the 2-speed axle switch circuit.

Insert the appropriate test lead into the 2-speed axle switch signal pin of the OEM harness connector.

Insert the other appropriate test lead into one of the other pins of the connector. Connect the alligator clips to the multimeter probes. Measure the resistance.

The multimeter
must show an open circuit (100k ohms or more).

Remove the lead and check all other pins.

The multimeter
must show an open circuit (100k ohms or more).

If the circuit is
not open, there is a short circuit from the wire connected to the 2-speed axle switch signal pin to any pin that measured less than 100k ohms.

Repair or replace the wires in the OEM harness according to the vehicle manufacturer’s instructions.

Isolate the 2-speed axle switch circuit. Turn the keyswitch to the ON position. Set the multimeter to measure VDC.

Insert the test lead connected to the positive (+) multimeter probe into the 2-speed axle switch signal pin of the OEM harness connector.

Disconnect the negative (-) multimeter probe from the test lead, touch it to the engine block ground, and measure the voltage.

The voltage
must be 1.5-VDC or less.

NOTE: An external voltage source is any wire in the OEM harness wiring that carries the voltage.

If the voltage value is more than 1.5-VDC, there is a short circuit between the wire connected to the 2-speed axle switch signal pin and a wire that is carrying power in the OEM harness.

Repair or replace the OEM harness. Refer to Procedure
019-071.

Connect all components after completing the repairs.