I was called to a house for no heat. I discovered that the fuse was blown. Trace Tstat wire for shorts, found none. Found heat strip relay melted, replace relay and terminals for wires. When I turned the power on the fan started running. I checked for 24V between red and green, nothing! I removed green from the board, still running. The high voltage for the fan black and yellow(common) come directly from the board in the air handler. Even with the t stat wires removed the fan still runs. The relay is part of the board I believe. I can't read the model #, the only word I was able to read is "International". Any ideas on how to get control of the fan, replace the board? By the way, heat, cool, etc. Still works fine, cycles on and off.

Thanks for any replys

Sure sounds like your going to need a new board. Normally I would say you have an open high limit, which would cause the blower to run nonstop, however, this would also cause the burners not to light. You said the heat works fine, but the blower just never shuts off? If so, its time for a new board.