ac problem

i got a Prostar with ac problem, i put 4 cans of dye in the ac system and looked everywhere for a leak in the bunk under dash tracked all lines condenser it blows fine for a day then after a day it blows hot air until you put a can of freon in it again then back cold, ac compressor always turning even when it blows hot air all fuses and relays are good, idk where else to look
EDIT........ when the fan is off compressor running and blowing hot air the low side is at 45psi high side at 200-350psi and at 350psi the fan kicks on and then the gauges read at low side 25psi high side 140psi, when the truck is off it equals out like it pose to but the low side is at 77psi high at 140psi,

 

yes i checked the evaporator in dash and in the bunk, i checked ac compressor and pully

 

no

 

There is no evaporator under the pass side seat, i checked the lines that goes under the cab to the bunk and there good, i for got to say its a 2016 year, im thinking its the high pressure switch but that still dont count for where the freon is leaking from if it is leaking but it has to be if i can add a can in it and it will blow some what cold for a day and then just blow hot

 

i done sprayed everything down with soap and water no bubbles or dye to be found any where