Which of these causes could be immediately eliminated if a compressor is defective?

• A. Defective Indoor Fan Motor
• B. Low Refrigerant Charge
• C. Clogged Condenser
• D. Open Thermostat

Answer: (A)

When diagnosing a compressor that’s not functioning, focus on whether the problem is with the compressor itself or with components that don’t directly cause the compressor to fail. The indoor fan motor’s job is to move air across the evaporator. If that motor is defective, you’ll likely see poor cooling or ice formation on the evaporator, but that issue doesn’t inherently cause the compressor’s internal components (like the pistons, valves, or crankcase) to fail. So, if you already know the compressor is defective, the indoor fan motor problem can be ruled out as the direct cause of that compressor failure.

The other factors—low refrigerant charge, a clogged condenser, and an open thermostat—can directly influence how hard the compressor works or whether it runs at all. Low refrigerant can cause the compressor to overwork or seize due to liquid slugging or insufficient lubrication; a clogged condenser raises discharge pressure and stresses the compressor; an open thermostat prevents the system from energizing the compressor when cooling is called for. Because these conditions can lead to compressor damage or mimic compressor failure, they remain plausible causes and aren’t immediately disqualified.