What causes an AC hose just to blow. I was checking a connection on the fan when the engine started to shutter and almost stall then it went back to a normal idle and it started to shutter when the ac hose blew up right in my face. I am just trying to find what could I have done wrong or was I in the wrong place at the right time. Oh by the way its a 97 accord

 

Maybe the A/C compressor relief valve failed or stuck.

 

To test the fan motor, the engine doesn't need to be on.

 

Overcharged 134a

 

Either it was completely coincidental, or your testing the cooling fans had some bearing on the episode.
IF you had interrupted the fan's operation for too long, the refrigerant temp may have risen to the point where the hose failed.
This doesn't happen often, and I think it's coincidental, bearing any other issues you may subsequently determine.

P