What follows is a very general answer.
If the questioner could add some more details to explain what kind of appliance or equipment is being asked about, then it is possible that a much more helpful answer could be given.
An electrical thermostat's element operates a switch. If either the element or the switch get worn out or damaged, then the switch may either stay open all the time or it may stay closed all the time.
If the switch stays open all the time there will be no current supplied to the appliance and it will stay cold. If the switch stays closed all the time the appliance will overheat because the current does not get turned off when the normal operating temperature has been reached.
If an appliance has been allowed to overheat then the insulation on internal wiring, or other internal parts, may have become damaged in such a way that a short circuit could be caused. Such damage would make a protective fuse blow every time the fuse is repaired or replaced.
If this is what is happening, the appliance itself will have to be repaired or replaced.
there is a short somewhere in dash or heater, you need to fix that to stop fuses blowing
Find out why the fuse is blowing. You have a short or the circuit is overloaded.
The alarm is built into the body computer and can not be removed. If you are blowing fuses, you have an short to ground or a current overload.
There is an electrical short to ground in the fan switch or in the blower motor itself.
The 50 ampere engine fuses is blowing because more than 50 amperes of electricity is passing through it.
could be that the regulator in the alternate is failing and causing power surges in the electronics and the fuses are blowing to prevent damage to the device and vehicles wiring.
One of the reasons you heater may not work is the thermostat. If the car keeps overhrating or the temperature gauge or light goes on/up could mean thermostat needs replacing if not not too sure why. Part is not very expensive I dont think. you need to carefully check all the fuses again /i did mine and looked at fuses all ok so i thought look again one not working hey presto /nothing to do with thermostat
There is a short somewhere.
Where is a principal fuses to cigarrete port in a front suzuki XL7 2006 no working and fuses is good?
Are you blowing fuses or are the bulbs blowing? Blowing fuses would be a sign of any wires or metal contacts in your brake circuit grounding out or shorting on themselves. You'll have to check all of the wiring in your brake light/switch circuit to be sure.
Check switch
If the climate control is not working on a Mondeo the fuses should be checked. If the fuses are found to be working then the wiring feeds should be looked at.