No power to thermostat

broken fan= furnace shutdown in most cases since the fan must push enough air to close the sail switch to start the gas flow.

measuring across the thermostat leads may not show any voltage. you aren't measuring between a hot and ground. just switch for the hot lead.

best way to test is to just short the two wires to the thermostat. If the furnace starts then but not with thermostat that means thermostat is bad. If it doesn't start with the wires shorted together, then there is at the very least a furnace issue.

Just replace the fuse found broken. But the fan still make really loud noisy.
Turned off before due to noisy and opened the heater and found the fan was broken, and hit the switch next to the fan. Not sure if the noisy can be cleared after the replacement of fan.
Not old machine, but had noisy since I bought it, and gradually became serious.

Did you turn the rocker on heater off then on again? it's a reset button. Are there any lights on the control board lit? Why did the thermostate turn off in the first place? Not clear on something in heater broke statement?

enblethen wrote:
Mae sure it is the thermostat by connecting the two wires together. the furnace should start immediately and then produce heat in 15-20 seconds. Then separate the wires and furnace should go into cool down and shut off.
Check to see if the circuit breaker on furnace is not tripped. Small red or white button to reset.

Uses multimeter to test wires on thermostat, get nothing.
There is on/off button on heater, it's on. Anything else I need to check?

Thanks

Mae sure it is the thermostat by connecting the two wires together. the furnace should start immediately and then produce heat in 15-20 seconds. Then separate the wires and furnace should go into cool down and shut off.
Check to see if the circuit breaker on furnace is not tripped. Small red or white button to reset.