The answer to 'condenser smells bad' is that a smelly condenser unit is often caused by mold, mildew, or rotting organic matter buildup. This can happen if the condenser is not properly maintained or if there is a lot of debris, leaves, or other organic material around the unit. Symptoms include a musty, rotten, or unpleasant odor coming from the condenser.
To fix a smelly condenser, you'll need to clean it thoroughly. This typically involves removing the outer casing, spraying the coils and fan with a commercial condenser cleaner, and wiping down the interior and exterior. It's also important to clear away any debris or vegetation around the unit to improve airflow. If the smell persists after cleaning, there may be a more serious issue like a refrigerant leak that will require a professional HVAC technician to diagnose and repair.