[cypress TX 72]

Also, I forgot to put in the last post.
The pressures that you are looking for are
at start up you should have around 200-230 high side and 40-60 on the low side. then as the truck starts to warm up you will see the high side go up and the low side go down.
When the truck is cooling inside and the doors are shut - you'll get down to about 30psi on the lowside and then the compressor should cycle. At that point your head pressure will be at 250,260, or even 270 depending on how hot it is outside and your fan clutch.
I am pretty sure that that compressor cycles at 30psi it may be as low as 25 or so - but by that point it will be blowing cooooooooold anyway.
T