Faulty wiring though a common problem of the air conditioner it could be quite a serious one. A faulty wiring can cause fire incidents and at the same time it can prevent the AC from getting power or the circuit breaker can trip off.
Refrigerant leakage: It must be noted here that the level of refrigerant in an air conditioner do not go down due to constant usage. The only cause of dwindling levels of refrigerant is a leak. When due to a leakage, the AC does not have enough refrigerant the unit might not able to produce the desired level of cooling. In such a scenario refilling the unit with refrigerant is not the solution rather mending the leak is a recommended thing to do.
Non-working of the outside fan: It is the outside fan that carries the heat from inside the house to the outside air. When the outside fan does not work properly, the heat transfer does not take place properly and the result is the compressor might overheat and trip off and in worst case some internal problems might be caused in the compressor.
Electric Control Failure is also one of the common problems faced by air conditioners. It is possible that the compressor and the fan of the AC wear out due constant turning on and off. This mostly happens when a system is over sized. Moreover corrosion of the wires and terminals of the air conditioner is also a common problem and that is the reason the electric connections of an air conditioner needs to be checked at regular intervals so that no such problem takes place.
Another very usual problem with air conditioners is water leakage. Water leakage in an air conditioner can happen due to numerous reasons like improper installation, clogged rear drains, and low outside temperatures or it could also be a faulty condenser.