[rattlsnak]

I have a central air/heating system and the blower will not turn off even with the thermostat in the OFF position. It is gas heat and electric air but I dont think that matters. Its dark now, but Ill go up and check it in the morning, but i ASSUME, that the thermostat sends signal/power to the blower, or a fan relay, where it then uses house power to run. It is an older system without any of the new electronics stuff the ones of today have. Sound right?

I think i read its a 24 volt system?? But I would think the fan runs on 120 typical house current, but something is 'telling' the fan to run, and it is, so i can eliminate the house power to the fan. I have located the source wire from the thermostat to the blower. What voltage range should i be checking for? 24 vdc? I would think if I have power there, then the thermostat is bad, but if not, then the blower relay is bad..

Anything to add?