FREE home air conditioning repair Anyone needing free help with there home ac system repair, make a post and I can walk you through what may be wrong. With my direction you can go through the systems operation step by step. This may save a costly service call. Here is a list of items to check first that may cause your ac system not to operate. Not in desired mode, heat or cool setting at the thermostat. Ac unit or fan/furnace breaker off or tripped. Plugged furnace or air handler return filter. No heat with a gas furnace, check for gas being off. Turn thermostat to off, wait five minutes, and set to desired setting. Did it restart and operate properly ? No,  Next  turn power off to system, wait five minutes and power back on. Start and run correctly ? By doing the above you just did a soft and a hard  reset of the operating board. If the above tips didn’t work, post here and I will help. Click comments at the bottom and view other posts and repairs.