Ac question , please help

Ok , I have a 04 kw t2000 c15mbn , it's got a newer sanden pump , last year along with expansion valve and evaporation canister ? I've been having issues with it freezing up where it would blow cold then get some what warm and spit moisture from vent , shut off for bit and back on be fine , well the other night had it on high went to bed and woke up cooking , vents were blowing warm , shut it off bought big ac refill can with gauge ( figured it just needed a charge) hooked up and went to charge but clutch wasn't engaged and gauge said 100lbs in red , shut truck off , was able to free spin clutch so good there , grabbed light tester power at pump , power at switch now when I pulled the sensors on top of expansion valve (two on top one on bottom , not sure what are witch ) and touched the light tester it lit up and clutch engaged on either one , and the one on bottom dead ... Any help please hopefully I don't need to bring it back in .. thanks guys

 

Any ideas ? I know there's some ac guys in here as I've read your post but nothing that's quite the same as mine