Have you checked the 30 Amp fuse ?
* A heat riser valve
check your thermostat first
a heating coil. Like a blow dryer
my 94 explorer wont blow heat
2005 nissan altrema 4 cylinda heat on blows cold when i speed up warm air will come out
An air conditioner blows out heat
heat it with a small blow torch and it will free easyer
find the two hoses that run from the engine block to the firewall, they should be about the thickness of a garden hose. Disconnect both of them from the firewall and connect them together. No water will ruin in to the heater core=no heat or leakage.
the heat blows out the defrost when it should blow out floor vents only
Fuses blow because of a over-current (short circuit) or over-heat condition. Look for a short circuit in the tail light circuit. It is also possible that the terminals at the fuse block are corroded, causing heat, which might be causing the blowing out, but highest probability is a short circuit.
Check the colant level, it may be low.
So it has something to heat and blow back out, thus, heating your home. The stuff coming out of your vents has to come from somewhere..