My blower run continue even I trun off the system at the thermalstate.
My blower use a relsy not contral broarf.
My blower have three wire white black and red. So the what (w) conect to com from the transformer and main power. Redconect to the relsy.
I replace the relay but not help.
What should I for to fix it?

The relay should close when 24 volts is present, and the contacts should open when 24 volts is removed. A short in the control wiring may keep relay energized. Verify contacts open when voltage is removed from relays coil.