[brcidd]

Let's think about it---your car has 25 psi in system--- your can from parts store has 80-90 psi in it-- you attach it to low side port on system- can is warm and 80 psi will push into 25 psi system until it equalizes at about 70 psi--so halfway into the flow of refrigerant the compressor will kick on automatically (when system pressure hits 47 psi). It may take 5 minutes- but so what....

Remember- that the red yellow green on the gauge only apply when compressor is running......

Now think again--- your system has leaked 97% of its refrigerant (25 psi static tells me that). If this was a tire- and you fixed it by "adding air" - you would soon go flat again, and you would say it was "not fixed". So same applies to a/c system- just because you added refrigerant, it will soon "go flat" again- because you have not found and fixed your leak.

Big hint- look at the compressor body- they tend to leak on compressor belly.

If you still want pin-outs of pressure transducer- I have them...