so it has finally cooled off enough for the A/C to not be running all the time. The other day with dreams of 100 MPG in my head I decided to switch off the A/C, normally I let the climate control do its thing. Now the A/c will not engage, the compressor never comes on. What have I done? Where should I begin to look?
A little help with A/C
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stevec5000
New member
Did you turn the temp down so it's lower than the interior temperature?
It normally goes on and off all the time by itself so not coming on this time must just be a coincidence if the controls are set properly. If the fuse hasn't blown then it might be low on freon.
It normally goes on and off all the time by itself so not coming on this time must just be a coincidence if the controls are set properly. If the fuse hasn't blown then it might be low on freon.
If the compressor clutch does not engage, the Compressor Relay may be defective. Click on the link below for more information.
http://www.sparkys-answers.com/2009/06/2003-toyota-4runner-ac-stops-cooling.html
http://www.sparkys-answers.com/2009/06/2003-toyota-4runner-ac-stops-cooling.html
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MidwestT4R
Member
I can't tell from what you wrote, but did you actually try the A/C button all by itself, without using the auto climate control? Fan on high and a/c on?
What about when you turn the vent to defroster only. Does it click on then?
What about when you turn the vent to defroster only. Does it click on then?
Martinjmpr
New member
+1 on this. You have to give us more information.
When you say "the compressor doesn't come on", what does that mean? Did you push the "AC" button and if you did, did the light come on?
Here's the odd thing about the "Auto" climate control feature: If you manually turn off the AC, it will NOT come back on, no matter what you do as far as adjusting the temp. You have to manually turn the AC back on in order to get AC again.
And yes, I had to learn that one the hard way, too (I like to turn off the AC when I'm about 5 minutes from my final destination for the day so cold air doesn't sit in the AC ducts - this helps prevent mold from forming.)
If you push the AC button and the light comes on, then adjust the temp down to its lowest setting and the AC should kick in noticeably.
FWIW, I hate the HVAC controls on the 4th gen. Why take something simple and make it complicated? I've finally gotten where I understand the controls a bit better but it shouldn't be that hard, Toyota should have come up with more intuitive controls.
I also hate the fact that with the headlights on, the panel lights are so dim I often can't tell whether the AC is on or not. Does anyone know if there's a way I can put a brighter LED in there? Or maybe just a different colored one? The amber LED isn't as easy to see during the day as the green LED on my 3rd gen.
BlackWorksInc
New member
Yes and no, if there was no refrigerant in the system it would cycle once or twice and then no longer cycle as the system realized low refrigerant. I would get a hold of a DMM (digital multi-meter) or voltmeter at this point and check the circuit. Since you already replaced the Relay, unless you got a bad relay that portion of the circuit is fine. I would start from the fuse box at relay and test for voltage. Then turn the A/C on with the vehicle running (please be careful with stray cabling and hand placement as you do this) and back-probe the A/C Compressor Magnetic Clutch. If the system is commanding the clutch to engage but it is not engaging the most likely culprit is a failing magnetic clutch. This part can be replaced individually of the compressor, but usually requires removal of the compressor anyways.
I will see if I can dig up a resistance specification for the magnetic clutch so you can better qualify your diagnosis.
Blackworks, thanks for that information, I'll meter it out this weekend. If the clutch is bad I will replace the whole compressor, found a Denso one online for $340. Since I don't have an a/c machine I will pay someone to evacuate it and then vacuum and charge after the install.
gshadow325
New member
my first post, and I would like to thank you for that link. I just bought a 03 v8 sr5 knowing the ac doesn't work for real cheap. since the stalkership miss diagnosed it as a bad compressor. someone replaced the relay in the fog light spot. my sr5 doesn't have floodlights! this same dealership also installed a brand new trans 20k ago at 145k. I am so giddy right now.
