COVER AS 1959337 - Caterpillar

Voltage Check
Put the engine start switch in the ON position. Do not start the engine.
Put the air conditioning system in the "AUT" mode.
Illustration 1 g00333238
Illustration 2 g00781373
If your machine is equipped with the control panel in illustration 1, refer to step 4. If your machine is equipped with the control panel in illustration 2, refer to step 5.
Manually override the system by pressing air conditioning override switch (3) .Note: After switch (3) is pressed, there is a 20 second delay before the magnetic clutch engages. Continue to step 6.
Manually override the system by pressing air outlet selection switch (3) until the defrost mode is selected. Note: After switch (3) is pressed, there is a 20 second delay before the magnetic clutch engages. Continue to step 6.
Illustration 3 g00607672
Unplug the electrical connection for the magnetic compressor clutch.
Check for DC voltage (24 V) on wire 513-OR.
A minimum voltage of 16 V is required for the magnetic compressor clutch to engage. If the voltage is within specifications and the compressor clutch does not engage, a problem exists with the refrigerant compressor.
If the voltage is not within specifications (16 to 25 volts), refer to "Control Test of Air Conditioning" in Testing and Adjusting, "Control Module-Test ".Resistance Check
Illustration 4 g00607672
Unplug the electrical connection for the magnetic compressor clutch.
Check the resistance of the compressor clutch coil. At 20 °C (68 °F), the coil resistance should be between 13 and 19 ohms.
If the coil resistance is not within specifications, a problem exists with the refrigerant compressor.