A/C problem with no code

... or, when you checked the pressure switch in post #10, did you remember to plug it back in after?

I've tried to think of clever diagnostic steps, but nothing came out any more clever than the "compressor circuit" steps in volume 1 (page DI-923 in my 2001 book, might be different in your 2002).

I assume your amplifier has the same "actuator check" mode my manual describes (DI-864 in my edition). In that mode, with the temp knob at max cool, I would definitely expect it to light an LED in the CLR MG socket. (Assuming the LED and resistor are good and the + LED terminal is in slot 1, - in slot 2...)

Strange problem....

-Chap

 

... maybe the amount of refrigerant charge isn't optimal, maybe various things to diagnose if necessary, but I think they all get easier to diagnose if you fix the problem preventing the compressor running, which it seems like you're pretty close to doing.

A multimeter at the relay coil terminals instead of an LED is fine.

-Chap

 

Wisco, what are your system pressures high side/low side? Too high or low those pressure switches will prevent your relay from energizing the coil....
Well you got your clutch to dog in, there's some progress...

 

Tiny house! All the rage lately. Are you going to power it off the Prius? Chapman can advise you on inverters...
I don't know if your pressure switches make or break to turn compressor on...but you could get a can of refrigerant at Wal-Mart with the hose and gauge all attached, for $15. keep it really clean and use that to test pressure- if you didn't actually use any refrigerant it wouldn't be too sinful to return it......tho I do like to squirt a little refrigerant thru the hose just before I skin the hose connector onto the port, to purge air out of the hose.
If you have never recharged AC before, there's not a lot to it, Youtube has some great videos.
Not likely that you are over on the high side but very possible you are under on the low side and that will cause the compressor to not kick in-don't be misled on pressure by that squirt of refrigerant you got when working on the sensor.
The low side test and fill port is a little hidden from view, centered under the hood, just under a black hose. It's not the port over on the passenger side.
Last year my Saturn was so low it wouldn't take refrigerant, and I had to hot wire the compressor clutch for the first half pound or so to help the gas to feed in. Then the low pressure switch did it's thing and allowed the compressor to stay on for the rest of the charge.
Proper working Prius AC is a powerful system. My 02 is a dark color, but on a sunny at at 88 degrees it cools the car down quickly and I have to turn it down. Hope you have the same luck with yours.

 

So, the correct charge is when you add about 100 more grams of refrigerant past where the bubbles in the sight glass just disappear (under the specified operating conditions). What did you notice in the sight glass while you were doing this?

How were you holding the can of 134a? With the outlet at the top so only vapor was drawn off, or could you ever have tipped it enough that liquid refrigerant ran out? In the liquid state it's not compressible, so feeding it into a compressor is a way of asking the question "what happens when an immovable object meets an irresistible force?"

Continuity between the pressure switch pins (from a couple of posts ago) did mean that your pressure was within range (or the switch was bad ... but if it was bad it was stuck showing the pressure was ok).

-Chap

 

Ok, that was bothering me ever since I wrote it, since I've got a manual here with page AC-49 clearly showing how to replace the dryer and filter, but I was having no luck finding those as parts.

Of course they're on the engine cooling system/radiator drawing, because the condenser's integrated. Et voilà:

88474-47010 dryer

88377-22010 filter

As for the O rings on the cap, I still haven't got a clue.

-Chap

 

Wisco, could your ac compressor not kicking in be clutch still slipping? I remember you said warped plate...
When I had a slipping clutch, mine pumped for a bit and made cold air, then kicked out, with the light blinking.
I think you are using a bypass wire, would this sidestep the lock sensor signal on a slipping clutch.....might be that all that is left is a mechanical, not electrical problem at this point, and it's just the lock sensor doing it's job...or still too low on charge to satisfy the low pressure limit switch.
I don't know how long it has been since my car was last charged, but when I charged the system last week, I used Chapman's method of 100 grams past the no bubbles point and my duct temp improved from 20 deg. below ambient to 30 deg. below ambient and the difference in performance is stunning!
Anyway, I had a warped driven plate and it slipped enough for the lock sensor to kick it out often. when I pulled the driven plate I could see only half of it was making contact at all. I ground it so it had more full contact and then it worked well enough to stay engaged all day and cooled well.
I have since replaced the entire clutch and kept the old, bastardized working one for a spare. If you think your clutch is slipping you are welcome to borrow it for testing by substitution, just refund my postage when you return it.
Chapman's post above also gets into drier replacement. If you go that route and dump the charge, Autozone will loan you a vacuum pump free for a $150. deposit. Robert.

 

Just to be clear, I didn't mean to suggest that sounded like anything Wisco needs to do at this point ... just that it came up earlier in the thread (when it seemed possible removing the lock sensor had vented the charge) and it had bugged me that I couldn't find the part numbers, so I wanted to make a note when I did.

-Chap

 

Yup, that's what I am suggesting may be happening...car sensing clutch slippage due to the warped driven plate in the clutch, necessitating your bypass wire to stay engaged...
About debris.....wonder if you could blow it out backwards by pulling the cabin air filter, close all outlets except one and blow into that with compressed air, maybe have a shopvac hose stuffed in the cabin air filter hole and stroke the heater door during the blowdown...in Iraq we had a lot of trouble with fine dust plugging the evaporators.