I was working under the hood recently just after driving around and I noticed that my AC components, i.e. that little tank behind the battery were kinda hissing a bit. I felt the plumbing and it was cold, as if the AC was on. I double checked to see if I dorked out and was driving with it on, but it was off. I suspect that a relay may be stuck, keeping power on to the AC circuit. Is there such a relay, if so, where? Otherwise, thoughts and input are appreciated!

99 F-350 Lariat 4x4 V10 CC LB SRW

 

You may not have had it in the A/C setting, but several settings utilize the compressor. Such as the defrost.

 

Didn't know that....Thank you!