shouldn't the fuse system stop a motor short or motor fail on blower motor? on 2010 Ford F-150

I had my truck running for two minutes when I smelled something burning. I realized the A/C wasn't working and opened the hood. saw the compressor working fine. Got back inside, shut off the A/C system and saw smoke coming out of the dash, grabbed a shirt but it was too hot to put out the hot melting plastic. So luckily I had an extinguisher and put out the fire in the dash and floorboard. So why didn't the fuse system prevent this?

2 answers 1 comment
poss under warranty at dealer
Any add on equipment or accessories at all?
All stock, just 98 degree day and white truck in color with window shades, as averages go the outside heat shouldn't have been a factor either