I have a Trane Air Conditioner/Heat Pump. It is about 9 years old. This summer it has started to act up. When the AC comes on the outside unit works fine, the inside fan will start to run then shut of and on several times for about 10-15 seconds. After that it runs fine and cools the house with no other issues. It does this every time the unit turns on. Any suggestions.

Is the fan being supplied with power when it shuts off? My guess is, it is not & the problem lies with the fan relay on the control board.