air compressor

Ok I think that is whats its called. It is the compressor that is connected to your ac unit. Now the question I have, is it normal for it to kick on and off so much. When I run my defroster the compressor kicks off and on every 5 secs. Is this normal or is ther a problem I need to know about. Also real quick, I noticed during the summer that my ac didnt work right. It would only blow out real cold air sometimes and then it would back off and blow out just warm-cool air. Figured it needed charging. Haven't charged it yet but thought maybe someone would know about this also.

thanks

auk

What year is it?
the compressor engages in defrost mode to remove humidity for the air, reducing condesation on your windows.
On/Off cycle Every 5 seconds is indicating a problem. Could be low on freon, or could be bad pressure switch.....