HOUSING 1745698 - Caterpillar

Error Codes
Table 1
Monitor Diagnostic Error Codes
Code Problem Area Problem
779–12 Blend Door Motor Defective Position
2357–4 Evaporator Sensor Open Circuit
2357–5 Evaporator Sensor Short Circuit
2938–4 Recirculation Air Temperature Sensor Open circuit
2938–5 Recirculation Air Temperature Sensor Short Circuit
5761–6 Blower Motor Open / Short Circuit
5762–2 Pressure Switch Abnormal Refrigerant Pressure
5763–2 Air Outlet Motor Defective Position Inspecting a Wiring Harness
Electrical problems are often caused by faulty electrical wires that have either an open circuit or a short circuit. The following procedures explain the test for an open circuit or a short circuit:Reference: Refer to Schematic, "Air Conditioning Electrical System" for the correct electrical schematic.Test for an open circuit.
Turn the battery disconnect switch key and the key start switch to the OFF position.Note: A separate electrical wire must be used to perform an open circuit test. Any harness wire can be used.
Install a jumper (connecting wire) between the two electrical wires at one end of the harness.
Use a multimeter to check for continuity across the two electrical wires at the other end of the harness.
Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.Note: If there is continuity between the electrical wires, the multimeter will have a reading of less than 5 ohms. If there is not continuity, the electrical wire is faulty. The electrical wire should be replaced with another wire of the same gauge.Test for a short circuit.
Turn the battery disconnect switch key and the key start switch to the OFF position.
Disconnect the electrical wire.
Turn the multimeter dial to the 200 ohm range and measure the electrical resistance.
Use one multimeter probe to contact the connector of the faulty electrical wire.
Use the other probe from the multimeter to check for continuity across all other electrical wires in the same harness.
If there is continuity between any of the electrical wires, the multimeter will have a reading of less than 5 ohms.Note: If there is not continuity, the electrical wire is faulty. The electrical wire should be replaced with another wire of the same gauge.