eihter the thermostat is messed up or you have a short in the wiring.
If your central air will not come on, you may want to check your thermostat battery and your fuse box. If this doesn't solve the problem, an HVAC repair service can help.
I had this problem with my 106 and it turned out that the thermostat was broken.
Here are some things to check. Is the thermostat turned up? Sounds silly but I went into many homes it was turned down, or the switch on the thermostat was turned to off Is the pilot lit? This assumes you have a standing pilot furnace. If it is spark ignition, does the park cycle start. Check all fuses and breakers
I would suspect the thermostat is stuck open. Replace the thermostat.
Thermostat setting may be same as room temperature ,therefore boiler will not ignite
A 2002 Ford Explorer would have come from the factory with approximately a ( 192 * Fahrenheit engine cooling thermostat )
Bad or frozen thermostat
Two things. Check the thermostat, or change it. 2nd, air lock in the system. And, a possible 3rd, the valve that opens the air vent might be jammed.
maybe check the thermostat.
It would do that if the AC is turned on.
The normal direction of circulation in the coolant system would push the coolant out the thermostat opening.
It is possible, but the engine would be very hot before this happens.