1. The Obvious Checks (Do these FIRST):
* Blower Motor: Is the fan blowing at all? If not, the problem could be a blown fuse, a faulty blower motor resistor (common failure point), a bad blower motor switch, or a malfunctioning blower motor itself. Check the fuse first, then test the resistor and switch (often requires some electrical testing).
* HVAC Controls: Are the controls working correctly? Can you switch between heat and AC, adjust the fan speed, and change the vents? If the controls are malfunctioning, they might need repair or replacement.
* Check the Coolant Level: For the heater to work, you need sufficient coolant. Low coolant prevents the heater core from warming up. Check the coolant level in the overflow tank and add coolant if needed (use the correct type for your vehicle). A leak in the cooling system could also be the culprit.
* Simple Checks (If Blower is Working):
* Temperature Control: Make sure the temperature control knob is set correctly (not on "off").
* Air Distribution: Ensure the air vents are directed where you want them to be.
2. More Involved Troubleshooting (If the above checks don't solve the problem):
* HVAC Blower Motor Resistor: This component controls the fan speed. A failing resistor often results in only the highest fan speed working (or none at all). This is a relatively common and inexpensive part to replace.
* Blend Door Actuator: This is a small motor that controls the mix of hot and cold air. A faulty actuator can prevent hot or cold air from reaching the vents. Often makes clicking noises when trying to engage.
* Heater Core: If the heater isn't working, the heater core (a small radiator inside the car's cabin) might be clogged, leaking, or otherwise faulty. This requires more involved repair as it's located within the dashboard.
* AC System: If the AC is not working, the problem could be with the compressor, condenser, evaporator, expansion valve, or refrigerant level. This often requires professional diagnosis and repair as specialized equipment and knowledge are needed to handle refrigerant.
* Vacuum Leaks: The HVAC system in many older cars relies on vacuum lines to control various functions. A leak in these lines can prevent proper operation.
* Fuses and Relays: While you've checked the blower fuse, there might be other fuses or relays related to the HVAC system. Consult your owner's manual to locate these.
3. Next Steps:
* Consult a Repair Manual: A repair manual specific to your 1994 Oldsmobile Cutlass will provide detailed diagrams, troubleshooting guides, and specifications. Haynes and Chilton are popular brands.
* Online Forums: Search online forums dedicated to Oldsmobile or GM vehicles. Someone might have experienced the same issue and can provide valuable insights.
* Professional Mechanic: If you're not comfortable diagnosing and repairing the issue yourself, it's best to take your car to a qualified mechanic. They have the tools and expertise to diagnose the problem accurately and perform the necessary repairs.
Remember to always prioritize safety. Disconnecting the battery before working on any electrical components is crucial. If working with refrigerant, be aware of environmental regulations and use proper handling techniques (or leave it to a professional).
