How should you troubleshoot LG air conditioner problems? Troubleshoot an LG air conditioner by checking for common problems such as power supply problems, fan issues and dirty condenser coils. By checking for these issues initially, problems that are more complex can hopefully be detected and fixed. What is an air conditioner protector screen? If the LG air conditioner is not working, first check to make sure that the power cord is plugged into a working electrical outlet. Open the breaker box or the household fuse, and check for tripped circuit breakers or blown-off fuses. Reset tripped circuit breakers, and replace blown fuses with new ones. If the air conditioner is not cold enough, the condenser coils or air filters may be dirty. Open the grille on the AC unit and remove the air filter. Clean out or replace the air filter as needed. If the problem continues, examine the condenser coil to see if it is dirty. A dirty condenser coil prevents the unit from dissipating heat that was removed from the air.