gas
You could be leaking coolant, your blower fan might not be working, etc.
Could be several things. If the blower works on A/C or vent it is good. If the Heater core is not leaking (due to corrosion, which is a common problem) it is probably good. Could just be the Temperature cable is off the the blower door not allowing air to pass over the heater core. Just to name a few..........
leaking what??
Your engine may have a leaking hose connection or a leaking gasket at the water outlet. It could also be a leaking hose.
If the noise is a squeaking sound, it could be coming from the bearings in the blower fan. It could also be coming from a worn bushing or bearing in the blower motor.
the food you eat can get caught in your braces, leaving bacteria that could stain your teeth. then they turn yellow like the sun
It could be leaking from a number of places. Some could be a simple fix and others not so simple. Need more info as to where it is leaking.
fuse, wiring, blower motor, blower motor switch, blower motor resistor
check your fuse, check the wiring to the blower or the blower motor itself could be shot.
The blower resister could be bad, or the blower switch could be failing. Check the resister first, it is commonly mounted at the rear of the blower housing under the hood.
Could be, Blown fuse, Bad blower motor, Bad blower motor speed resistor, Bad blower switch,
the windings inside the blower motor can be shorted out fan will work but takes too much power could be a schafed wire as well or the blower motor could be seizing up..