1. Basic Checks:
* Refrigerant Charge: Even after replacing components, the system might be undercharged. Make sure a qualified technician re-evacuates and charges the system to the correct specifications.
* Leaks: Even with new components, there might be a leak somewhere in the system. Use a leak detector to check all connections, lines, and the evaporator core.
* Compressor Clutch Engagement: The compressor clutch should engage when the AC is turned on. If it's not engaging, check the clutch itself, the wiring, and the AC pressure switch.
* Blower Motor: Make sure the blower motor is working properly and is delivering enough airflow.
2. Deeper Troubleshooting:
* Expansion Valve/Orifice Tube: If the expansion valve (or orifice tube) is faulty, it can restrict refrigerant flow and prevent cold air from reaching the vents.
* Condenser: Although you replaced the condenser, a clogged or partially blocked condenser can reduce its efficiency. Inspect it for debris or damage.
* Evaporator: The evaporator core might be dirty or blocked with debris, reducing its cooling capacity.
* Thermostat: A faulty thermostat can prevent the compressor from cycling on and off properly, leading to inconsistent cooling.
* Electrical System: Check the AC control panel wiring, relays, and fuses for any faults or damage.
3. Specific to 1998 Chevy Trucks:
* Common AC Problems: 1998 Chevy trucks are known for issues with the AC compressor clutch, the expansion valve, and the evaporator core.
* AC Control Panel: The AC control panel in 1998 trucks is notorious for failure.
* Check for Service Bulletins: Look for any service bulletins related to AC issues for your specific vehicle year and model.
Important Notes:
* Professional Assistance: This is a complex system, and attempting to fix it without proper training and tools can be dangerous. It's best to seek help from a qualified automotive technician.
* Proper Equipment: A professional will have the necessary tools, including a vacuum pump, refrigerant scale, and leak detector, to diagnose and fix the issue.
I strongly recommend taking your truck to a qualified technician for a proper diagnosis and repair. They'll have the expertise to pinpoint the exact cause of the problem and ensure a safe and effective repair.
