Compressor runs after switch is turned off

Hi folks. 2nd time around newbie here. I have a question for the electrical gurus here.
Firat off let me say that i got my conductor series set up about 8 years ago and had it on my fj cruiser at the time. Absolutely loved it and when it came time to sell the truck i just pulled it all out and stored it. Wrapped up and boxed.
Well i decided to reinstall it this past weekend on my tacoma. Pretty much a breeze with new brqckets and such. Plumbing of the air lines was simple. I say however i am not an electrician but got the wiring done. Tested the system about 5 or 6 times yesterday without a hitch. Compressor came on as it should and cut off at the high pressure setting.145 psi. This morning i was on my way to work and switch the compressor on and it of course came on no problem. However as im driving down the road i hear the comp shut off for about 30 seconds and then kick back on. I hadnt blown the horn so there was no reason for the comp to cut on as the pressure didnt drop. So i thought ok ill shut off the switch. Well after all the reading you just did here is the climax, i turned off the switch and the comp continued to run.
And run and run and run. So i pulled over and simply pulled the fuse from power to the compressor amd it shut off. Also there were no leaks. None big enough to drop from high pressure to low without it being obvious.
So why would it have cycled perfectly 5 or 6 times yesterday. And then today the switch is cut off but it continues to run?
Is the pressure switch bad?
Is the on off switch bad?

Anybody with any help would be appreciated. Thanks in advance.

Sounds like a solenoid is stuck closed