prompt
Contact with refrigerant can cause injury.
This system is always pressurized, even when the engine is not running. Never heat a system already charged with refrigerant.
Contact with refrigerant can cause frostbite. Keep hands and face away to prevent injury.
12.2021 Caterpillar ECM ECU Flash Files Full Set Download
Always wear safety goggles when the refrigerant lines are open, even if the pressure gauge shows no refrigerant in the system.
Be extremely careful when disconnecting connections. Loosen the connections slowly. If the system is still pressurized, evacuate the system to recover the refrigerant before disconnecting the connections.
Inhaling refrigerant through a lit cigarette can cause personal injury or death.
Inhaling refrigerant gases from a lit cigarette or other smoking methods, or inhaling the fumes from burning refrigerant gases, can cause personal injury or death.
Caterpillar ET 2026A & 2019C Electronic Technician Diagnostic Software Download and Installation
Do not smoke while servicing the air conditioner, or in any situation where refrigerant gases may be present.
Move the machine to a level surface before inspecting the air conditioning and heating systems. Lower all equipment to the ground. Ensure the gearbox is in neutral or parked, and that the parking brake is engaged. Keep all other personnel away from the machine.
Heating System
To perform a performance check on your heating system, please follow these steps:
1. Run the engine at 1000 rpm.
2. Set the temperature control knob to the highest heating setting.
3. Turn the heater fan switch to the high position.
4. When the engine coolant temperature is within the normal operating range, the air flowing from the vents (air ducts) should be warm.
Fault 1: When the heater control knob is set to maximum heat, almost no or no warm air flows out.
1. Perform the following steps:
a. Check the engine coolant temperature. The coolant temperature must be within the normal operating range.
b. The heater control valve must be functioning correctly. Check that the linkage from the temperature control lever to the heater control valve is adjusted correctly. When the temperature control knob is set to maximum heat, the heater control valve must be fully open.
c. Check the heater hose for blockages and bends. Blockages and bends in the heater hose may cause coolant to stop flowing through the system.
d. Check the valve that connects the heater hose to the engine block. Ensure the valve is adjusted and fully open.
2. Repair or replace all damaged parts.
Electrical System
Problem 2: No airflow to the cab. The evaporator blower motor does not operate after the fan switch is turned on.
1. Perform the following steps:
a. Check the circuit breaker or fuse for open circuits.
b. Perform a visual inspection of all wiring connections. Use the electrical schematic for your specific model.
c. Check the fan blades for obstructions.
d. Check that the fan switch operates correctly in all settings. The evaporator blower motor should operate in all settings. The evaporator blower motor should operate in both cooling and heating modes.
e. Use a 5P-7277 voltage tester or a 9U-7330 multimeter to check the voltage of all components in the electrical system. For further information about the machine, please refer to the Electrical Schematic section.
2. Repair or replace parts if necessary.
