06 a/c & power issues

I have a 2006 impala 3.5l....just noticed that when i turn my a/c on the light only flashes then turns back off, also having reduced engine power with no warning messages or check engine light.....any idesa?

Take it to Autozone and get it scanned . you can have codes that don't show up with a " check engine " light but can be detected with a scanner .