Trane A/C blower fan won't shut off.

[Fred B]

I have a home ac unit (Trane), about 2 tons,. The blower fan will not turn off once it starts. Even if I turn the thermostat to the off position. I have to turn off the circuit breaker to stop it. When I turn the breaker back on the fan will stay off until I restart it at the thermostat but will then stay on again. I have tried a different thermostat unit. Fred B

[Java_Bob]

There is a fan relay that is controlled by your stat, it could be sticking.

[jnaas2]

How old is your furnance, the older ones had a fan high temperature limit switch that when it failed would sometimes cause the problem you are describing