My ac kicked off and a red light appeared on my AC button (didn't even know that existed) and of course, hot air blowing. What's up with this?

 

I don't know which models exactly but Honda uses a sensor on the AC unit that reads RPM. Then matches that with engine RPM. If it senses a difference, to keep from burning up belts, it will cease function of the Compressor clutch. I think this only applies if the AC compressor shares a belt with the alternator. And, I believe the red light is the indicator that this is happening. I can't recall for sure though, anyone else have input?

 

Foot is right; according to another source, the red light IS an indicator of mismatched RPMs. Ok, to further expose my ignorance, what is the fix, replace the compressor?

 

I bet it is because the clutch is slipping. IF it is the problem, you can replace the clutch without replacing the whole compressor.