2009 Camry 2.4 ac blowing hot air

Hey guys, 1st time poster, need some help here. Im stumped on this ac issue. 2009 camry 2.4, variable displacment ac compressor that has the internal lock up clutch which spins all the time. Car isnt blowing cold. There seem to be 2 issues right now. One is there is a big leak, it had nothing in the system. I filled the system and added some dye to find the leak. And still no visible leak, my suspicions are possibly the evap core, however i didnt have access to a sniffer today to test it. The 2nd issue is, the compressor doesnt engage, even when refrigerant is filled.
Ive checked a wiring diagram and it seems there are no relays or fuses, and the compressor has 1 2-wire connector which gets power from the ac amplifier. Ive check the ground, and it is good. Ive checked the power, with key on, ac on high, and im reading 2.6v on the power side. I didnt hace access to any specs for that.
No codes, yet the scan tool seemed to show some different ambient air sensor readings. Live data had the amboent correct at 95 degrees Fahrenheit, however when doing some bidirectional tests, it stated 36 degrees Fahrenheit which seems odd however idk if that sensor input would not allow the clutch to engage. So I decided to check the sensor resistance and it was within spec for the ambient temp.

Using a scan tool I was able to breifly command the clutch on. So id think the ac amplifier signal to the compressor should be good. I see there is a solenoid valve in the compressor that can get stuck sometimes. As well as a transducer which subs in for hi/lo pressure switches.

Now obviously there is a big leak somewhere, iam suspecting the evap core, but cant be sure until i put the sniffer up the drain tube. But what tests can be done to gain some direction here? Any help or info is appreciated

Make sure the system is charged and bridge the high side pressure switch only if its a 2 wire connector otherwise you risk shorting out your 5 volt reference and knocking your computer out... see if itll come on that way

Its a 3 wire transducer

Dont quote me 100% on this but a 3 wire pressure sensor for you a/c you gonna have a 5 volt reference a ground and a sensor signal wire.... youd need the key on and back probe the connector frok battery neg and mark your 5 volt ref wire.... one of the other 2 is gonna be the signal wire... now u can unplug the sensor.. back probe and get a reading on both wires if both are 0 its a pull up design and ud need a diagram to do that test... if one of the 2 wires reads 5 volts also its a pull down design you can safely jump that signal wire straight the ground

what are your pressure gauges reading? If the Low side is high and the High side is low (pressures are about equal) then I would visually check the front end of the compressor to see if the center shaft is turning, if its not then the compressor has locked up. I looked at the wiring diagram and I did not clutch on this model.

Yes this model has an ac magnetic clutch and a magnetic clutch relay... power passes thru a diode before entering the control side of the relay energizing it and enabling the compressor clutch

Hey Scorps! So just to confirm, the clutch does engage when commanded? Did the air temperature at the vents improve during engagement?

Do you recall where you saw the 36 degree reading, exactly? If it was the Evaporator Temperature Sensor, then you might be onto something. :huh: I'm not certain what the programmed cut off point is, exactly, but I bet 36 degrees is close to it. If the Amplifier suspects the evaporator is freezing, it'll deny clutch engagement.

If you do find that it was the Evap Temp Sensor that's irrational, I'd dig around the HVAC case and find that connector. If you can substitute in a variable resistor to produce a higher temperature reading and get the AC to blow cold, then you're onto something.

FWIW, the variable displacement solenoid on the compressor will draw about 1A when commanded fully on, and you'll get a near constant power feed from the A/C Amplifier at the same time. These systems are 'variable', but in my experience, they spend most of their time wide open. :lol:

I didnt command it on long enough to see if it blew cold, due to ot was low om refrigerant at that point. Also this system doesnt have an external magnetic clutch or relay. The signal comes directly from the ac amplifer and the clutxh pulley spins at all times. The clutch locks internally.

I will check on monday, and see if itll blow cold. At this point i think i need to find the leak and fix it, and procede to diag this compressor issue.

What do you think the mgc relay is??

Like I stated, there is no magetic clutch relay for this specific system. There are 2 different ac systems in 2009 camrys. 1 uses an external magnetic clutch and mgc relay. The other uses a variavle displacment compressor, internal clutch and NO relay. The later is a less understood system, and the one iam working on.

Theres no need for any attitude posts asking what I think am mgc relay is? Doesnt matter what I think it is since ive been pretty clear that is not the system at hand. I can provide the diagram for the correct ac system if required.

I don't know much (anything) about that system, but as far as finding the leak, there's some great free videos about just that on the ScannerDanner YouTube channel: