Just taking a guess but could be something with your relay or a bad pressure switch.
Those pressure switches that AIM sells SUCK ASS!!! A friend of mine had one and the compressor always ran. He got a the same one I did and it works great.SlammedDime said:What kind of adjustable presssure switch??? if its a kind like what AIM sells, not a square d one, then it kicks on at a 1 psi drop... so if you have ANY leaks, it will always be on.