2006 Prius A/C Temperature Stuck?

Maybe you're evaporator core is freezing up and you're trying to blow thru a brick of ice .?

 

There should be a sensor that prevents that, but running in manual mode with max. fan speed; you never know. You on recirculate or fresh air? How does your interior air filter look? You need to take a deep dive with techstream to see what all your sensors are seeing to nail-down the problem.
Your radiator fans may not be turning, so it can't remove the heat from the R134. It works while the car is moving, because your pushing air through the condenser.

Good Luck.....

 

What happens if you set the temperature to 68F, or basically anything other than MAX COLD?

You might want to verify that the drain hose from the evaporator core is flowing normally. It runs under the passenger side foot well carpet.

 

Manual flex temp probe up in drain hole will touch the EVAP core need about 14 inches of probe . Not too hard to make happen. Be like freezing with systems off because it's a block . Blow hair dryer not heat gun into floor or foot vent watch water roll out of drain tube . Melting .

 

^ Yep; if everything is working properly - the coils should be at or just above 32F to prevent the block ice effect.
IMHO; you really don't need to do the hair dryer thing. Just turn-off the AC compressor and keep your fan on; it should defrost naturally and drain out the bottom.
I know some AC mechanics that'll disable the coil temperature limiter, because customers complain that the unit doesn't get cold enough. That's what leads to the ice block forming; the compressor doesn't cycle-off when the coils gets too cold.

Just my two cents.....

 

I think your Ace evap temps are going to be in the 40s not really 32 maybe out at the gat hose or line coming off compressor sometimes you see the beginning of freezing they're same at you're house . Lotsa sweating and moisture rt they're. At least that's what I've experienced.

 

You connect gauges to the high and low side of the system and then you watch the gauges while the system running . When freezing starts to take place gauges start to act up gas and vapor no circulate properly etc . You can Google videos about people using gauges on HVAC systems to pinpoint freezing non-moving gas and vapor and so on . The expansion valve opens and closes as needed for processes to happen they can stick etc . Those parts are 20 yrs old now . Are the gas levels proper. Charge level can make some of this go on . I would check all the easy stuff first see what the system looks like with gauges connected and running Ive seen diagnostic setups to have gauges visible whilst moving the vehicle etc . I would think I would want to make sure that charge.. air content . Liquid or water . Desdicant . Is all up to snuff before I start doing $3,000 worth of work and ripping my Evsp box out. At least in my case personally so far and about nine of these cars I have not had to remove the EVAP case all AC have been flawless once correctly setup and sealed . And filled properly so far . That's one thing I will not live without is my AC it will become a winter car directly without it.

 

Ptem0 sensor in cabin or elsewhere is tests le easily.stuff in EVAP box not so much .if folks have pumped crap into system think stop leak .

 

The valve is part of the core. Stupid design. For gen 3 they moved the valve so that it is possible to replace the valve from the engine compartment. Not perfect access, but much less work than taking the dashboard and then evaporator core out to reach it. (Although, that is still apparently what Toyota service manuals recommend.)

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None of which is going to help on the OP's gen 2 though.

If it was mine I would:

1. Check (that it is there, not damaged) and replace the cabin air filter.
2. Use a Toyota evaporator core cleaning kit. It squirts cleaner up into the evaporator, washes off any dirt in there, and then the now dirty fluid drips back down through the drain hose.

If that doesn't fix it, take it to an A/C shop and have them evacuate, dry, replace the dryer sock, and refill. The goal being to confirm that the charge was/is correct and that the system is dry. See for instance the discussion here:

AC evaporator and low side line freezes up all the way to compressor,stops cooling.any ideas? | PriusChat

The blower moves air well when it isn't frozen up? If the air flow is compromised the evaporator will freeze up in a humid environment. I don't know what the humidity is like there now, but most of the year it is pretty damp in Florida.