Fan Running No Cold Air - AC Relay?

What makes you think there's a relay?

The A/C compressor has a 200+ volt three-phase motor driven at variable speeds by the car's A/C inverter, under control of the ECU for HVAC (sort of quaintly called the A/C "amplifier").

Have you asked that system for any diagnostic codes?

Blink (a/k/a Flash) Codes – How to. | PriusChat

 

The cool level looks okay what coolant are we talking about Is it red and in a reservoir? It has nothing to do with the air conditioning The gas or the freon that's in the metal lines can only be seen when you start the compressor so if you have someone sitting in the car turn on the compressor in the air conditioning on low high fan etc you should hear the air conditioning compressor come on and the sight glass which is right over by the windshield washer jug should show bubbles and then start to turn clear yours is probably staying clear in the compressor never turns on because there's little to no free on in the system so the low pressure switch protects the compressor and keeps it from coming on it uses r 134a gas

 

Read post #2.

 

If there is a reliable A/C shop near you I strongly suggest you have them diagnose the problem. (Not to cast aspersions, but you aren't even sure that your gauges are working.) At that point you can decide whether or not this is something you can fix yourself.

Evaporator failures are common in older cars, including the Prius, and when they go, there is no A/C. Also no freon. Big PITA to change one as the whole dash must be taken apart to reach it.

If that turns out to be the issue, consider doing the actuators at the same time. At 21 years they are living on borrowed time. Sometimes the actuators can be rebuilt (clean off all the old dielectric grease and replace with new, clean all the electrical contacts), but my recent experience with our 1998 Accord, which uses the same technology, is that the motors in the actuator may fail over that length of time. Unfortunately there is, AFAIK, no source of inexpensive high quality replacement motors. On the Accord I ended up replacing one of the actuators with one of the inexpensive ones from China. It may not last, but on that car it is relatively easy to replace, since Honda mounted the unit on a metal plate, and taking the metal plate out is straightforward since the fasteners for it face into the cabin, rather than sideways into an obstruction.

 

If you're turning the air conditioner on correctly not just pushing the auto button on the steering wheel and all that business but bring up the screen for the AC put the temperature part of it on LO not 71 or 83 or any of that just l o put the fan on high now push the AC button and put the yellow line over the AC button but if you can get somebody to do that while you're standing outside of the car looking at the sight glass where you see the freon with your eyes instead of the gauge. When whoever in the car puts on the yellow line above the AC button do you physically hear the compressor start to run You can reach your hand down there and put your hand on it there's nothing to get you there are fans there but you're not going to touch them you're going straight down to that orange plug You should hear it it makes a whining noise if they push the button and turn it off now it would you would notice it go away? You don't hear any of this or you do when that noise starts if you're looking at the sight glass you should see bubbles moving across the sight glass and as the compressor runs more the bubbles will get less If it's operating correctly If it's staying bubbly that's not good. Now you could stick your gauge on the low side which is opposite from where you're looking the fat hoes when you put your gauge on the fat hose it should read right around 40 lb in the green if you're way down at 20 PSI or something like that well you can add gas just for the heck of it until you get it to hold around 37 close to 40 You don't have to power it to 40 35 to 37 on these compressors and anything above that and it'll start laboring and you'll be heading into shorting out the compressor zone If you get the 32 33 PSI on the low side and the fat hose is ice cold. You're good disconnect your business and run it for a couple hours it'll get stable and if it's happy it'll make plenty of cold If it's not and it's hot in the morning or in a couple hours or in 30 minutes you got a leak Don't bother with that it's going to cost $2,000 to fix got to tear the whole car apart this will become a winter car.

 

Look here my friend when your air conditioning system at rest there is no high and low side If you were able to connect the gauge on the high and the low side simultaneously like most air conditioning people do you would see around 100 lb on the both gauges because there is no high and low side until the compressor starts to pump freon and creates a high side and a low side via making the system under pressure the compressor that is. So sitting not on with a gauge on the low side you're going to see about 90 PSI The minute you turn the air on with that gauge connected it should suck down to around 37 you will see this on the gauge the minute the person in the car pushes the AC button.

 

Well, not except maybe in very unusual circumstances. There are 3 actuators: blend (hot/cold), mode (where air comes out), source (fresh/recirc). The latter two cannot affect the temperature, they just change the air path. Maybe if the motor is fully warmed up and blend is stuck in the hot position then you might not be able to feel the A/C, but I think probably even then you could tell. Also the car would be blazing hot inside whenever the motor has warmed up and you have not reported that.

How long have you had this car? If it is a recent purchase somebody else may have messed up the A/C. If it is from a shady source, they may have tinkered with it to get it to work long enough that somebody would buy it, and it has now reverted to its broken state.

 

A pressure gauge on a bunch of refrigerant at rest is nothing but an overcomplicated thermometer. When the refrigerant is at rest its pressure will simply track the temperature it's sitting at. You can look up the pressure on a chart like this one and see what the temperature of the refrigerant is.

If the gauge reads 60 psi, it's about 62 degrees Fahrenheit in there. If you add more refrigerant, as soon as it's all equilibrated to 62 degrees Fahrenheit again, some of the gas will have condensed to liquid it will still read 60 psi. If you let some out, some of the liquid portion will vaporize and it will still read 60 psi on the gauge if it's still at 62 degrees temperature. If it's 80 or 90 Fahrenheit, you'll see around 100 psi like Tom says.

So, all told, a pressure gauge is a pretty disappointing way to try to tell how much refrigerant is in a system. It's just going to keep reading the saturation pressure off the temperature chart. Until you've lose so much refrigerant that there is no amount of it remaining in the system as liquid. Then you'll see lower pressures, as it won't be obeying the saturation chart anymore when none of it is liquid.

 

Watching the grass grow type work right they're. If used to late model antics in shops this won't be too bad . Here it becomes a fall winter car . Unless it might be over top nice ....

 

Not sure if they still do, but Toyota used to sell a kit to clean out the evaporator. Couple of cans of stuff (foaming cleaner plus something else) which were sent up through the drain hose into the evaporator to clean it out. It was never clear to me if that cleaning would extend the life of the evaporator or just make it smell better. In fact, the web is full of claims that cleaning the evaporator will make it last longer, but I have yet to see anybody with actual data to support that. (Found one site that said it was best to pull it out of the car for a more thorough cleaning. Yeah, sure buddy, gonna do that this weekend before breakfast. Fit right into my schedule. For the rest of the morning I will paint the whole house, which will leave the afternoon free for a complete house repipe. Not sure what activity to do for the evening, maybe paint the car?)

 

Well I've had a whole bunch of Toyotas evaporators out all the way back to 68 KE Corollas they had hang on air conditioning units made by denzo right under the glove box and boy did they blast some cold air out with it Tecumseh type upright compressor that almost shut the engine off when you turned it on No kidding those earlier evaporators were pretty stout I would challenge somebody to get a hole in one of those they were serious Gray looking things with fins that you couldn't even move with your fingernail they were stout and there was a expansion valve right in the box right next to this evaporator so you had to split the box to get to the evaporator the seal of the box and the expansion valve replaced a few. Then moving forward into about 85 87 these evaporators started to get really chintzy. You could look at one and tell you didn't want to touch it let alone try to install it look like it would just fall apart in your hands practically You run your fingernail across the fins and they would all just buckle and what have you Not nice And then after that they got a little more cheap and I think they've pretty much stayed the same and heater cores took a real dump they became plastic tanks like the radiators were in the mid '80s and all of that and they failed a lot of them left and right the heater cores. I can't imagine cleaning and evaporator with foam in the system from Toyota and there's you know I think four seasons makes the same kit with the foam and the stuff you squirt and evaporator case and then you run the air and so on and so forth your air is always going to smell funny when you turn it on because there was water in there an hour ago so you get that musty smell for a second I don't know how you're going to get rid of that some big fancy charcoal filter something maybe reach in and turn the car on and put the air on before you sit down stand outside 28 seconds You probably won't smell anything when you get in