All of a sudden the lights in my house have started flashing every 4 minutes or so. This did not happen before today and it is happening on lights on different breakers. I noticed the main panel was making a clicking noise when they flashed. I am not tripping any breakers. I narrowed the clicking down to the A/C breaker and replaced it. The clicking is gone but the lights are still flashing. If I turn the A/C breaker off the lights stop flashing. The flashing has been happening all day every 4 minutes. I know it has something to do with the A/C and my best guess is the system is the A/C is short cycling. How can I test for this? The unit seems to operating normal although the fan does seem to be moving a little slow. If it is short cycling is this something that is inexpensive to fix or would I likely be looking at a new unit? Also is there anything else that could be causing the flashing. Please note I have checked and tighened all connections in the main box.