Have HVAC Questions? Ask an HVAC Expert for Answers
Look inside the blower door for a wiring diagram. Tell me what you find and tell please about how old the furnace itself is, that will help.
We can go from there.
Thanks, ***** ***** case, if you can send me a few pictures, close ups, and distance shots showing the complete controls compartment I might be able to mark those up with workable trouble shooting instructions.
Use the paper clip icon at the right end of the tool bar above to send the pictures.
We need to look for signs of a bad heat exchanger while we are at it, look for big chunks of rust under the burners, and especially look for changes in the flame pattern in each burner when the blower comes on... any leaks will put carbon monoxide into the home, that is especially dangerous for children it can cause brain damage in children.
Thanks, ***** ***** is a printed circuit card that the thermostat wires run directly to, there is a high probability that has a defective solder connection deep inside the card.
If there is no printed circuit card (older furnaces mostly), then it is likely that fan relay or blower limit control is bad.
Without photo's or a diagram there is not much else I can say, we can however go from there if you feel you need whatever scant input I can provide in this situation.