Either you have no power or have a bad fan relay or motor, this can be determined with a volt meter if you have one.
First off I would try the fan On switch, this will show you if you have both high and low voltages if it works, if not then you must check breakers, fuses and transformer as well as circuit board fuse a 3 amp auto type typically.
An air conditioner blows out heat
Portable air conditioner will not blow cold air. What to do?
i have a pioneer travel trailer, air conditioner the compressor does not come on please advise is there internal switch?
about 5 minutes
It's out of freon or refrigerant.
I have a 2003 X type Jaguar and the a/c does not come on when it's 45 degrees outside. Why?
diagram for 1999 chev subarban air conditioner
The air of your Chevy trailblazer 2004 blow out of the front vents when the air conditioner is on because the air condition is faulty and it needs repair.
Hmmm, because it should?
The system can be low on refrigerant
Not likely
If it does blow just not cold air you should see if it needs to be recharged