On Jan 27, 9:14*pm, (Lp1331 1p1331) wrote:
The blower is controlled from the furnace, not the thermostat, when the
thermostat is set in the "auto" position for the fan. It either
controlled by a mechanical bi-metal thermostatic switch or by time delay
from a circuit board. York residential equipment is not all that common
in my area, so from the model I couldn't tell you off the top of my head
which yours is likely to have. How old is the furnace?

20 years old. I've been trying to find a parts diagram without any
luck. I suppose they don't really want you mucking about in there.
But its got to be a big old industrial part. If it's a time delay on
pwb, then, damn, $$$$$ I suppose.