PseudoK

I jsut pumped in a $25 can of r134 into the system expecting the compressor to kick on, and it still doesnt, I found out that these cars have this self diagnostics for the AC system and got these three codes.

23 is AC Pressure switch, which some say could just be low pressure in the system, I just put a nice sized medium large bottle. should I risk another $25 bottle to see if maybe it was really low, or what else is there to really check

My AC blows litterally HOT air, on vent and with AC on, nothing but hot

would 42 and 43 really prevent the Compressor from coming on?

sjc2467

Blindly adding refrigerant is never a good idea. What are the system pressures (high and low side)? Check those before adding any more refrigerant. If you don't, you will almost certainly overfill it. If you don't have access to a manifold gauge set, you can get one pretty cheap at harbor freight. The quality is quite poor, but they will work for occasional DIY use, and if you combine a 20% off coupon (search online) and a sale, you can get it for about $30.

Is the compressor clutch operating? What is the temperature of the suction line near the compressor?

The codes 42 and 43 are for the inlet and outlet dampers (the electronic "valves" or "doors" that control where air comes from and where it goes to). It's trying to move them, but the position sensor value isn't changing. They could be stuck, the motors could have failed, the position sensors could have failed, or it could be a wiring problem. The fact that you have both codes means it's more likely a wiring problem or something like that, because it's unlikely that both systems would fail at once. Check connectors and harnesses that they have in common. I'm guessing you are not able to change between recirculate and fresh air, and you cannot change where the air blows out? Whatever is causing those problems may also be causing a problem with the blend door, and/or those faults, or something else, is causing the blend door to default to full heat. In the case of a serious malfunction, automatic climate control systems usually default to full heat, because that's more "important" than having a/c.

You should also check the pressure switch circuit. If there is a problem with that circuit, the a/c will never work.

PseudoK

I have a gauge off of the "AC pro" recharge bottle that I kept from another time, it seems to work, it displays the pressure in the green for my Impreza. but it displays Zero on the Lexus

just to be sure: I am using an aluminum adapter on the port that I believe to be the right one

that plastic plug seems to get in the way.

sjc2467

So you have an r12 system that has been retrofitted to r134a...? You can remove one of the two brackets on the a/c compressor, which holds the wiring. That will allow the wire to be moved out of the way to allow the quick-connect fitting to be connected, and the second bracket (leave it in place) will still be more than sufficient to hold the wiring securely out of harms way. There is a ground wire under the screw for the bracket, so be sure to replace the screw without the bracket, to maintain the ground connection.

(Yes, that is the low-side service port, and that is where you add refrigerant.)

The gauge displaying 0 is very important information. Assuming you have verified that the gauge works (you can hook it back up to your other car, if you need to), that means that there is no pressure in the system. Assuming that you actually added refrigerant (as you said), that indicates that there is a big leak somewhere and it is leaking out as fast as you can put it in. That requires a pretty big leak, so you will probably be able to see signs of oil around the leak and/or see the actual leak itself. You may also be able to hear it leak. If you cannot, your best bet is to add some UV dye to the system, and add just a bit more refrigerant. The UV dye should mark the location of the leak. However, if the leak is so fast that the refrigerant leaks before it can mix with the dye, this method may not work.

To properly diagnose or charge an a/c system, you need a low side and high side gauge (systems that use thermal expansion valves and/or variable displacement compressors have very specific pressure requirements, and you can substantially over or undercharge them with only a low-side gauge). However, in this case, even a single gauge is enough to tell you that the system has a serious leak, which will prevent it from operating.

Note: if the car has not recently been run, the pressure in the system (with the car off) should be roughly the same as the ambient temperature in degrees Fahrenheit (70-80 degrees corresponds very closely to 70-80 psi). Both the high side and low side will be the same. So, assuming you're seeing 0psi with the system not operating, there is virtually no refrigerant in the system. (You cannot charge based on this pressure, however, because once you have the correct amount of refrigerant, you can keep adding more, but the pressure will not increase because the refrigerant condenses to a liquid above that pressure.) The only accurate way to charge the system is to pull a complete vacuum and add the correct weight of refrigerant. Charging by high and low side pressures can approximate a proper charge, but is not particularly accurate. Charging by low side pressure alone may be enough to make the system work, but you will never be able to charge the system accurately, so it will not work as well as it should (undercharging will reduce performance and overcharging will reduce performance, consume more power from the engine (wasting gas), and can cause damage to the system).

PseudoK

so if its big enough to release the pressure as I put it in, then could it be a gash, where I have to replace the whole line?

PseudoK

ok while replacing my front bumper I think I found the reason why I dont have any pressure...




I am really hoping that they are connected with a single line, and that this isnt two different lines missing.

also thats an adapter I put on myself, its not retrofitted, I bought the adapter for my Impreza. I find it odd that the connector required for these AC recharge connectors start in 93, but both my 93 cars dont have it.. even a high end one for its time..

Brianmoss

Haha yeah that's gonna probably be your problem.

PseudoK

ok I went to pick and pull and got a line from a 95, everything looks right, but it doesnt really fit in the hole, its too big.


I was thinking about trying to tighten the screw in to bring it in or hammer it in a bit, but I dont want to mess up the aluminum or strip the screw holes


I have a 93 why isnt this working? I really want AC..