With compressor running pulled switch off suction accumulator and compressor continued to run. What do u mean by with the key off you mean with the truck not running? I'm not sure if there is an orfice I would think these trucks would have an orfice.
yes when you key off the truck that is running.
Since everything appears to be working and you can't even turn off the compressor with the ac switch in the truck, I agree with Jlope82, sounds like a short or bad module.
For reference the cycle switch and the compressor high pressure cutoff switch are in series and go the VCM to tell the VCM to interrupt or not the ground path to the clutch relay coil, turning on/off the clutch. The high pressure cutout switch is normally closed and probably never cycles in its life. its there so the compressor doesn't pump its guts out onto the road because of the charge being too high or completely blocked path. By chance can you measure the idle pressure of the charge with the truck sitting and not having run for a while. how much higher than 50 Psi it?