Unit was working great till, my wife messed with thermostat controls while I was away for the week.. since then blower fan won't quite running.. I have reset all factory settings on thermostat,neither in heat or ac mode will blower shut off,it won't shut off when I put it in fan on or auto, the ac kicks on & outside unit runs to temp. but blower won't shut off, I then went to thermostat a trane tcon401 & completely disconnected from base & blower styill runs in air handler,handler unit is a trane,twh030b1401a.. I opened up blower door & fan kept running,I shut off at breaker next to unit ,it didn't appear that contacts were bad,any help would be great.. hate to pay that service call if its an easy fix.I just want to update, the honeywell 9217 brown relay switch was changed out, still fan keeps running, could it be the little circuit board,

I will avoid any comment about who caused what but doubt that your wife caused the problem. She may have touched the stat but if the fan runs with the door open there are other issue that a muddled stat. I would not both trying to fix this or to call for repair. I set the stat to ON when I move into a home and there it stays until I move out. Fan running 24/7 actually uses only slightly more electricity than when on the AUTO setting. The home will be more comfortable and a more even temp between rooms and floors.

I was leaving fan run ,but here in Florida with the attics getting so hot the fan will start pushing hot air into ducts,because attic & poorly insulated flex duct gets warm awful fast,

To continue I was able to determine that it was actually the circuit board ,connected to the relay,when I tested across leads it was shorted.thank you for replying... I realized last night after testing it wasn't anything my wife did,just bad timing.

Getting new part Monday.. call & ac parts placed ordered for 31 plus tax.

Are you running AC much of the time? If your ducts are heating up naybe you should consider wrapping the ducts in insulatio if adding insulation to the attic is out of the question