air conditioner is not working

We need to start with checking pressures. If your system is low then the compressor will not come on. You need a gauge set that will test high and low side pressure. Let me know what they are and we can go from there.

It appears your vehicle doesn't have a traditional AC relay. It calls it a MG/CLT relay. If you can locate this relay in the engine compartment fuse box (right side of the engine) we can check that as well.

I attached the info about this and the process to test it. If this is the one that was empty then we need to put a relay in and retest the system.

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

All set. it was just low.I feel stupid not to check that be for every fuse . Thank you.

Awesome. I love it when it's an easy solution. Glad you got it figured out. Please come back to 2CarPros next time and thanks for the update.

The AC just started blowing hot air! I was told Toyota AC are hard to diagnose. All the fuses look okay. The Freon was checked and said it was okay. A friend hooked up Techstream program and was able to turn the clutch on and AC was working but stopped as soon as the program was turned off! He said it might be the compressor. I just want to know if there is anything else I should check before I go out and get a compressor.

Good evening.

No, they are not hard to work on at all.

No, to the compressor. If he activated the compressor and it blew cold air then it is working.

It sounds like an electrical issue turning the compressor on.

Did you check all fuses with a test light for power on both sides?

Roy

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Thanks for the response . I did check the fuses with a multi meter but I will double check them again with a test light and get back to you!

Sounds like a plan.

Keep me updated.

Roy

Hi, sorry it took so long to get back to you. I checked all the fuses with the test light and they all looked good.

I was able to get a couple of pictures from Techstream that might help you.

The first one is with the ac on full but the clutch not engaged.

The second one is when I forced the clutch on with Techstream.

I noticed the pressure going up a lot on the second picture so I shut the clutch off. Also, both the fans on the radiator did not turn on at all and the air was not cold. I checked both fan fuses and they looked okay. I did not test them with the light because they are 30 amp box type and not sure how to test them. Any help would be appreciated!

Okay, that does not give me any pressure readings. I need pressure readings on the high and low side.

The AC may be off due to low Freon level or the low side pressure is below 20 lbs.

Roy

Okay. I will get the gauges from my buddy this weekend and let you know what reading I get.

Do you need the static readings and the reading when I have the clutch engaged in Techstream? Would that also be the reason the AC condenser fan does not come on? I thought it always comes on when the compressor turns on.

Yes, both static and running with clutch engaged.

Roy

Okay. I got the gauges from a friend!

85 degrees outside temperature with car not running.

Low side 115
High side 175

Car running at about 2,000 rpm and manually turning on clutch in Techstream.

Low side 34
High side 255

Ran like that for a few minutes (both radiator fans were also on) then the high side just kept going up every time I turn the clutch on! I had to shut the clutch off in techstream!

I also got a trouble code of B1479.

I read that would be the code for the "flow sensor on the compressor".

I also read voltage for flow sensor should be above 3.8 when compressor is off. Mine was at 3.56.v. Could the sensor be bad?

Okay, from the static pressures, you need an expansion valve. That would also explain why the high side keeps going up.

You need to go through the wiring to find out why the compressor will not come on.

Roy

Looking for magnetic clutch relay where it’s supposed to be in fuse box is empty.

Changing the expansion valve looks like a big job!

What about the trouble code of B1479. Would the flow meter cause the pressure to go up? I read about someone who had a similar problem on a 2010 rav4 with the clutch only going on with the Techstream program and they told him it was a bad compressor?

Hello,

I have included in the diagrams down below your vehicle's J/B relay block where the A/C relay is located. I have it highlighted for you. It looks like it is a 5 pin relay that can be purchased at any auto parts store. Purchase the relay and plug it in. It only goes one way, and it should restore your vehicle's A/C system to operating conditions again. Please keep us informed.

Thanks,
Alex
2CarPros

That is not possible. If you command it on, then the compressor is good. It is the signal that is not activating the compressor.

B1479. I believe this set because you commanded it on and left it on. Doing what you did was intended as a test with key on engine off, not leaving the compressor run while the engine is running.

Roy

B1479/79
Item Description
Symptom/DTC B1479/79
Descriptor
Manual Air Conditioning System
Probable Causes
Air Conditioning Amplifier
Flow Sensor (Compressor and Pulley)
Harness or Connector Between Flow Sensor And Air Conditioning Amplifier

That didn’t work. where is the ac amplifier located?

Thanks again.

Do you know if the expansion valve on my vehicle can be taken out from the firewall side?

I could not find any videos on my make and model specifically, but some other ones show the bolts to get it off can be accessed from the firewall side while others show having to take if off from inside the car!

Hello again,

I have provided both the Engine Room R/B diagram and callout but also the Instrument Panel Junction Block diagram and callout for you in the diagrams down below. I have highlighted all of the fuses that have anything to do with your vehicle's A?C system. Please go through them and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros

It is done from under the hood at the firewall. Recover all the Freon, remove the bolt that secures the two lines to the expansion valve and then remove the two bolts that hold the expansion valve to the EVAP core.

Make sure you change the dryer as well.

Roy

I can turn on magnetic clutch with diagnostic machine and A/C blows cold when i unplug machine it turns compressor off.

Great. Does not look too hard. Thank you for all your help! I will order the parts and report back when I get it done!

Hello,

This sounds like it could be the relay that controls your A/C compressor has gone bad. I have already given you the relay information in the fuse and relay panels diagrams and callouts earlier, so you should be able to find it there. Here is a link for you to go to that will help you, if needed, bench test the relay:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Please go through these guides, if necessary, and get back to us with what you can figure out.

Thanks,
Alex
2CarPros

Great. look forward to hearing from you.

Roy

Checked all fuses and replaced relay and still no power to compressor.

Hi, Sorry it took so long for me to get back to you! I changed the Expansion Valve and the Compressor still didn't turn on. After researching the problem so more I found someone who had a Lexus who had the same problem and also got the B1479 code. Toyota has a TSB about it T-SB-0084-13. The Flow sensor has to have 3.8v with the AC OFF in order to have the amplifier tell the compressor to kick in! (mine was 3.59v) Toyota recommend changing the compressor because they don't sell the Flow sensor! I was able to find the Sensor on ebay for $50 and decided to try and change it myself!

I had to take off the front bumper, ac condenser(replaced drier) and radiator to get easy access to the Flow sensor on the compressor ( you may be able get to the sensor by just taking out the radiator) . I took the snap ring off the sensor and tried to lift up the sensor but it was frozen and broke off when I pulled up on it. I had to use a chisel to get the rest of it out. I noticed there was a lot of what looked like white rust or corrosion there so I scrapped out what I could and sanded it down so the new one would seat properly ! ( maybe The white rust was making the sensor not read correctly?). I got the new one in and put the snap ring on and then I checked it with Techstream and got a reading of 3.86v.(above the 3.8v min needed)! My old one was 3.59v!



I put everything back together and charged the system and the AC works now. A lot of work for such a simple part! I read the problem is with many Toyota models and years starting in 2009! Crazy how they let the problem last so long without addressing it and making people pay for a new compressor!

I just thought I would let you know in case someone else runs into the same problem!

TSB https://static.nhtsa.gov/odi/tsbs/2013/SB-10061590-2280.pdf

Here's a couple of pictures of the before and after Techstream Flow sensor readings!

Hello again,

Okay, the problem could be in your vehicle's A/C Amplifier. In the diagrams down below I have included a wiring diagram of your vehicle's A/C circuit as well as directions for the removal, inspection, and installation of the A/C Amplifier, which is located in the center of your vehicle's dashboard. Please go through these guides and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros

Good job.

I was more concerned that with the high going up to high, it would effect the signal voltage and that is why you had a bad reading with the old one.

If it did not change after the expansion valve replacement then the sensor was the next step.

Roy

Checked everything still no A/C the diagram says automatic A/C is it the same for manual A/C?

Just a clarification. The Flow Sensor needs to be checked with the AC off! Voltage has to be between 3.8 volts and 4.2 volts. If below that then the flow sensor is bad.

Thanks for all the help.

Hello again,

I'm sorry about that. Here are the wiring diagrams for the Manual A/C. They are located, as usual, in the diagrams down below. Please go through them and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros

A/C gets cold when accelerating, sometimes it will also get warm when driving. If I'm parked it will get warm and sometimes it stays blowing cold. I checked the A/C Freon level with my gauge and it's full. The A/C is just unpredictable. Any suggestions?

Correct.

This sounds like the compressor has gone out or the system is low on charge or a fuse is bad, these videos and guides can help us fix the problem with diagrams below to show you how on your car. I have included (below) the air conditioner wiring diagrams as well so you can see how the system works.

https://youtu.be/4UjfQKvrB6Y not working

and

https://youtu.be/uZrQCGwXfek recharge

and

https://youtu.be/yrhWKlQEPWw leak detection

and

https://youtu.be/4EqdrBVb0sY vacuum and recharge

and

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Let us know what happens and please upload pictures or videos of the problem.

Usually on a system that is proven to have a full charge, yet has issue cooling at times, cooling fans are the issue. At times a cooling fan can fail intermittently, usually after running for an extended period of time so I would pay close attention to it. Also make sure the front of the condenser is clean and clear of debris. When the vehicle is off, reach down and grab a blade of the fan and see how much play it has radially, it should have little to no play. If there is excessive play, then the fan/s are no good and must be replaced.

I appreciate this very much. I will look at all these factors.
Thank you

You're very welcome!