this is because you have a short in either the the ac circuit or the fan/blower circuit. You'll know know which one by turning the fan on without the ac, and if it doesn't blow the fuse then you know it's the ac circuit.
I had the same problem it was a shorted wire under the driverside causing the fuse to blow when you turn the ignition my downstream oxygen sensor wires shorted out (melted and fused together). check for anything shorted out connecting that fuse.
A loose or corroded ground wire will cause the fuse to blow. Check the ground wires on your brake lights.
One fuse controls the function of the hazard, reverse, and turn signals of the car. When there fuse blows all the components stop working.
For Ignition. Your car will not start if this fuse blows, generally if there is a short.
If a fuse blows you probably have a short or the circuit is overloaded.
Well the main reason why your car blows out cold then hot is because the air conditioner may not be working properly. You should go to the car shop and get it fixed.
The Air Conditioner is on
Remove the fuse from a/c circuit and then replace or repair your switch.
because when you first turn it on, hot air blows from it... thats just how it works, then after a while cool air comes
20 amps. the current that can flow through before it blows
convection
Sounds like it could be the ECM fuse. You need to have someone check it for a short.