I just lit my pilot light for my furnace. And turned it on. Now the blower will not shut off when I have the thermostat set on auto, or even when I switch it off. I have to go downstairs and switch the main power switch off. I changed the batteries in the thermostat. It gave me no trouble all summer with the a/c what could be the problem?

Probably an adjustment on the fan limit switch, this is the part that brings on the fan in the heating mode.

How do I find the limit switch?

Check the sticky at the top of this forum.

Please train my dog to fix the furnace fan or tell me how Thanks