The classic signs of a failing AC capacitor are: the outdoor unit hums or buzzes but will not start, the top fan sits still or has to be pushed to get going, the AC blows warm air or cools weakly, you hear a clicking sound near the unit, or the system trips off shortly after starting. If you open the access panel (power off) and see the capacitor's top bulging, domed, or leaking oily fluid, that is a dead giveaway. Capacitors degrade with heat and age, and Los Angeles summers are hard on them, which is why they are the single most common AC failure we see. The good news is the part is cheap and the fix is quick. The catch is that a capacitor holds a high-voltage charge even after you cut the power, so testing and replacing it safely takes a meter and a pro. If your unit is humming but dead, call LA Heating & Air at (818) 660-1062.
