AC Blowing Not Cold

It could be damage from improper oil added at one point in cars life.

 

Has that equipment been used with various car AC systems? I'm out of my depth, but Repair Manual cautions against using equipment which may introduce oil other than spec into the Prius system. Not sure how crucial that is, say compared to dumping a incorrect oil in.

We had lacklustre AC performance, starting about 5~6 years back, maybe a bit more. Went this route, no problems since:

 

A set of gauges are as "basic" as it gets for ac system diagnosis.

Has the ac ever worked (cold air) in your ownership? These systems get turn it up cold.

How did this happen? They don't come off by themselves. Was it the orange high voltage plug or the control plug?

The compressor is not loud. You "might" hear ir for a few seconds before both radiator fans engage - which are much louder.

I would record the high and low side pressures with ac set for high fan and Lo temp. Windows open on a warm to hot day.

Then when it was found to be low with some higher pressure on the high side you know the compressor is running.

You can check the saturated r134a temperature on your low side gauge and it should be over 32f.

At that point I would add r134a using refrigerant with no oil, dye or leak stop. Usually the cheapest small can. An ac guy's 30 pound can has no additives; neither should yours.

Slowly add no more than 12 oz while watching the site glass. Stop when it is almost clear; no bubbles.

If this cools it off you have a leak which must be found and repaired.

If the compressor never adds pressure it is not running. However adding gas will usually engage the low pressure switch and allow compressor operation if it is functional.

I would not be surprised if the compressor failed and someone unplugged it

 

Yep; those connectors usually have a "lock tab"; they don't just fall off....