BOOM AS 1527728 - Caterpillar

Diagnostics
Measure the value of the resistance in the actuator between GY/YL and L GN/RD. See "Specifications". Proceed to step 2.
If the resistance value is incorrect see step 3. If the resistance value is correct see step 4.
Replace the actuator.
Disconnect the connectors from the actuator and measure the voltage between the harness connectors GY/YL and L GN/RD (pins 1 and 3). See "Specifications". Proceed to step 5.
If the voltage value is incorrect see step 6. If the voltage value is correct see step 7.
Check the harness and repair the harness between the connector and the control panel. Also, check the source of the power system.
Fit the actuator and measure the voltage between terminals (pins 2 and 27) of the control panel. Measure the value at the MAX COOL position. See "Specifications". Proceed to step 8.
If the voltage values are incorrect see step 9. If the voltage values are correct see step 10.
Check the harness and repair the harness between the connector and the control panel.
Replace the control panel. Specifications
Resistance ... 6 kΩVoltage between connectors ... 5.0 VVoltage between terminals (pins 2 and 27) ... 4.0 V