my inducer blower will not come on unless the safety switch is unhooked from it. safety switches have been changed out with new ones and the gas valve is changed out with new gas valve. when you hook back to safety it cuts off.
Which safety and how did you test it? Were the ones you replaced testing bad along with the gas valve or are you randomly throwing parts at it hopeing to stumble across the real issue?
Call for heat from the thermostat will show 24 volts between C and W at the control board. The same 24 volts goes though all the safeties and if they are closed then the circuit board powers the inducer. Check each componet and find out where the problem is and then look into why that safety is open.
Normally when you unhook the low voltage wiring from the main limit the inducer motor and the main blower motor should turn on. This is to push any of the gases out of the system due to failure. Test the main limit and see if you have resistance through it.