Toyota Highlander Limited AC issues driving me crazy!

My wifes 2009 Highlander with rear AC is not cooling properly. The lowest it will cool is 60 when on the highway, but normally it will cool to 71 or so in the front and 65 in the rear. This is all i’ve done so far and i’m about at my wits end!
I’ve replaced both explansion valves (front and rear), new drier filter, new ac suction line with inline filter. At this point the only components left to replace are the compressor and condensor. Yes, I did vacuum the system out and it holds a vacuum. Yes, I believe I am filling it with the correct amount of R134A. Please see below pictures of the gauge readings last night while it was 81 degrees. What should I replace next? A toyota tech i’ve been messaging seems to think I have a blend door issue causing heat to mix with the AC. Any help or guidance on what to do next is much appreciated! Thanks in advance!

Front%20AC Gauges%2081%20deg

Under what conditions are you recharging the system?


Thats not something I recommand doing yourself…Please see a A/C tech for proper diagnostic.

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Are you referring to weather conditions? This last charge was last night, 81 degrees, a little humid. I’m in Mississippi. A friend told me it is best to recharge the system on a hot sunny day which i’ve already done, but not with the latest part replacement, (rear expansion valve). Thanks!

IMO, shops will just throw parts at it. I’d rather do so myself and save on the markup and labor. I’m afraid I may end up at a shop though.

No! No! No!

What are the operating conditions of the vehicle when you’re recharging the system.



LOL. Engines running and AC on full blast.

That’s wrong.


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Ok. Please enlighten me, oh wise one!

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Please see below pictures of the gauge readings last night while it was 81 degrees.



The readings are a little high… But is it so high as to make a big difference?

Let me ask you a simple question.

Prior to introducing refrigerant into the AC system, did you purge the air out of the manifold gauge set?


I guess not. I am learning and do not know about this step. Can you elaborate? How can I do so? After vacuuming the system for at least 30 minutes I closed off the valves, then turned off the vacuum. Then I opened the low side to fill it with the gas.

You also introduced air back into the AC system.

Take it to a shop.


There’s plenty of youtube videos out there showing how to purge and clear your gauge set. It isn’t rocket science but you need to use common sense.

No offense intended, but learning as you go is not something you want attempt when it comes to air conditioning systems in general. It has the potential to be an expensive lesson.

System was evac’d. You added the proper amount of Freon? 2+ lbs? Your suction line is frosty?

Yes. It was evacuated and vacuumed. I added the min 1.6 lbs. no frost that I noticed on suction line.

Everyone learned at some point. I’m gonna figure this out !! :muscle:

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Headed home. Wet and 72 outside and it’s blowing about 51.