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Ask Peter Bagley Your Own Question
Peter Bagley
Peter Bagley, Auto Service Technician
Category: Toyota
Satisfied Customers: 684
Experience:  master tech at Toyota dealer
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1996 camry ac light blinks and ac blows warm

Customer Question

1996 camry ac light blinks and ac blows warm
Submitted: 12 months ago.
Category: Toyota
Expert:  Joshua Davenport replied 12 months ago.

Good evening. If the A/C light is blinking on a Toyota, it means that there is a problem with the A/C system. The most common problem is the relay for the compressor.

Customer: replied 12 months ago.
ive already replaced that and it still has the same problem ive also replaced the ac control with one from a junk yard and still the same problem
Expert:  Joshua Davenport replied 12 months ago.

Ok. Is the A/C compressor coming on at all or does the light go straight to blinking?

Customer: replied 12 months ago.
the compressor comes on for 5 seconds the shuts off i can turn off the ac switch turn it back on and it comes on again for 5 seconds the shuts off again. i can jump the terminals at the ac clutch relay and the compressor comes on stays on and blows cold and the ac pressures read fine. the clutch doesnt slip nor does the ac belt
Expert:  Joshua Davenport replied 12 months ago.
Ok. The problem is in the magnetic clutch for the A/C compressor. The clutch is requiring too much current to operate. The control head detects this and shuts the compressor off to prevent electrical damage. Once the compressor clutch is replaced the A/C will operate correctly.
Customer: replied 12 months ago.
ok so can you explain why is it that i can jump the terminals in the ac clutch relay when i pull that relay out and the compressor stays running but doesnt shut off? keep in mind the ac switch doesnt turn off the compressor clutch either when i jump the terminals the ac will stay running until i remove my jumper wire. if what you say is true then if i keep the ac clutch engaged by jumping the relay terminals the excess current will eventually burn up the clutch. so if its an excess current issue at the ac clutch why doesnt the ac fuse blow? also is it possible the trinary pressure switch is bad where its thinking the high side pressure is mistakenly excessive and shutting off the compressor after 5 seconds of running? as you probablly know its a 4 wire switch that monitors the as pressure if its too low or too high and controls the cooling fan when the ac is in operation. thanks
Expert:  Joshua Davenport replied 11 months ago.

Ok. The A/C clutch is pulling more power than normal through the system. With the relay jumped with a wire you are eliminating the A/C switch circuit. The switch is what engages the relay to put power to the clutch. If the pressure switch was bad, the light wouldn't blink. The clutch would either cycle frequently or not at all. The only components in the system that can cause the light to blink is the Relay or the Clutch itself.

Expert:  Peter Bagley replied 11 months ago.

hi I'm a Toyota master tech may I shed some light on this problem?

Customer: replied 11 months ago.
hi can you read my notes from the previous mechanic about the the ac light blinking on my 96 camry ive tried 2 different relays and didn't work so let me know what you say about it. thanks
Expert:  Peter Bagley replied 11 months ago.

hi again , yes read those notes. I have a different opinion on your problem, number one , yes the blinking A/C light does indicate an A/C problem and by jumping the relay you are eliminating the rest of the A/C circuit and that's what we do to check to see if the clutch and compressor are working.so you made it a little easier for me to narrow it down for you.If the compressor was pulling to much power it would blow the circuit breaker but it's not and the A/C actually works right? so the next thing is this the drive belt is in good shape and not slipping right? make sure the charge pressures are right not over charged with Freon, especially on the high side when operating, this is important because if the pressure switch senses too high of pressure it tells the amplifier that and it starts to cycle too often, next if all that is correct the belt and pressures check out to spec then replace the RPM sensor located on the compressor making sure the wiring and connectors are in good shape. If this RPM sensor is faulty it also sends a wrong signal to the amplifier to cause it to cycle and not work properly. hope this helps and gives you a better idea how your A/C system works. good luck and let me know.

Customer: replied 11 months ago.
hello peter. where is this rpm sensor located on the compressor and can I get it at a auto parts store and is it fairly easy to replace? since your diagnosis is totally different from the other "certified Toyota mechanic" why would I get faulty info.from him? sounds to me that with just answer web site theres a good possibility that I can get wrong info and leading me to do unnecessary repairs to my car at my expense and time which is not cool. I appreciate your help and look forward to you reply back thanks, ***** ***** the way im a mechanic too but im not a Toyota specialist by the way the belt is fine and the pressures were reading fine and theres no cycling of the compressor it just comes on for 5 seconds and shuts off and I have to turn off the ac switch to get it to come on again and it shuts off again after 5 seconds all over again
Expert:  Peter Bagley replied 11 months ago.

hello again it;s Peter, yes my answer is totally different but I have been a Toyota tech since 77 and am a Master tech so I bin around for awhile, and when I saw him tell you it's the compressor I THOUGHT BEFORE YOU SPENT THAT KIND OF MONEY ON A COMPRESSOR i'D JUMP IN TO TRY AND HELP. iF IT WASTHE COMPRESSOR WHEN YOU JUMPED THE RELAY AND MADE IT WORK IT WOULD HAVE BLOWN THE HIGH AMP FUSE LINK WHICH IT DIDN'T DID IT? LIKE YOU SAID IT RAN AND COOLED THINGS DOWN. WELL LIKE i SAID WE DO THAT TOO TO ISOLATE THE COMPRESSOR FROM THE ELECTRICAL PART. NOW YOU HAVE TESTED THE REST -- PRESSURES ETC THAT LEAVES ONLY TWO ITEMS THAT CAN CAUSE THE PROBLEM YOU DESCRIBE. AND COMING ON AND OFF THAT FAST WITH LIGHT BLINKING BEST DESCRIBES THE RPM sensor or AMPLIFIER to be at fault and being that the RPM sensor is easier and cheaper to replace and try I would suggest to go there first. the RPM sensor depending on the part number of your compressor should be either on the lower front side , or the end of the compressor, as for where you can get one I don't know if after market parts carries them you may have to go to a dealer they can also show you where yours is located with your vehicle's vin number. As for cycling that is when the compressor turns on and off it's just now yous is double timing with a blinking light so the Amplifier is getting a wrong message and that only comes from one of two sources, the pressure sensor or the RPM sensor. to replace the amplifier is an expensive and time consuming job so that's why I'm recommending replacing the RPM sensor it is most common to do too. I totally understand your concern about conflicting ideas but even doctors and lawyers can sometimes agree to dissagree but hopefully come out with the same resolve to fix the problem. I hope this helps and please let me know if I can be of more help. good luck.

Customer: replied 11 months ago.
hi peter just to clarify things Joshua never said it was the compressor but the magnetic clutch that was bad and I went this route using this Just Answer web site to get some help and get as accurate as possible with the diagonsis. I will say that I had this issue on a 02 Solara v6 with auto air and the relay fixed the issue but as you indicate its not the relay every time and most of the Toyota blogs or you tube videos I watched all say the relay is bad or replace the oem blue relay with a newer one. at any rate the relay change dosent solve my problem. as my notes said I even went to a junk yard and got a used ac control head and that didn't fix the issue either so I will find out about this rpm sensor. also can this sensor be replaced without loosing the Freon? thanks Dean
Expert:  Peter Bagley replied 11 months ago.

To simply answer that if it were a clutch it wouldn't have engaged when you jumped the relay and most RPM sensors can be replace without evacuating the system but like I said check the model or part number first just to be safe. good luck

Customer: replied 11 months ago.
hello i checkedwith both advance auto and auto zone and neither one has this sensor so i called 2 different toyota dealerships and they looked it up and they call it a compressor sensor not a "rpm sensor" ive never heard of that and why would the ac system care about the rpm of the compressor since its dictated by the engine speed? any way that part which appears to be a dealer item only is 184.00 so it aint cheap and is too expensive to not be 100% sure that its the problem. also i looked at a aftermarket compressor at auto zone and saw no sensor on it but there was a small plate with 2 small bolts on the bottom of the compressor so i dont know if thats where it goes and do they make you use your old sensor when you replace your compressor? so im not feeling good about this. you never mentioned the high price of this part and what you call an "rpm sensor " toyota calls it a "compressor sensor". so what are my options in this matter? i want to be confident in the diagonsis of this problem. thanks. Dean
Customer: replied 11 months ago.
HI Peter i asked you a question swveral hours ago and havent heard back so could you please reply asap thanks.
Customer: replied 11 months ago.
hi peter i apoloigze it was around 8 pm so its only been a little over 2 hours since i ask my last question
Expert:  Peter Bagley replied 11 months ago.

well some parts are known by different names from different t areas or shops, we call it an RPM sensor because that's what it does, it senses the compressor turning and sends that signal to the amplifier which matches it to the engine rpm, if it don't then you end up with the problem your experiencing. as for you trying to compare the problem you had with a sienna and this one , if you would have jumped the relay on the sienna it would show you the compressor clutch wasn't working right away but when you jumped the relay in this vehicle it did intact work right? you can go ahead and replace the compressor and if you get a used one it may work for you because it will come with a different sensor that is working and may be a cheaper alternative, but then you need to evacuate the system and recharge it. check this link out https://www.google.ca/search?q=1996+camry+a/c+speed+sensor&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjR8LH4p67OAhVEKCYKHRMoBQkQsAQIPg&biw=1920&bih=955 like I pointed out you already confirmed the clutch and compressor works by jumping the relay and you tried the relay .look I've bin in the trade over 45 years and with Toyota since 76 and that's my gut feeling given the info you provided . like I suggested throw a used compressor assembly on it and recharge it and call it a day if that's the way you want to go, it may be cheaper then just the new sensor.good luck

Expert:  Peter Bagley replied 11 months ago.

Just checking in to see how your doing and what you have done so far.

Customer: replied 11 months ago.
Hi Peter sorry for the late reply but I don't get on my computer all the time and to clarify I used to own a Toyota solara not sienna. the solara is the 2 door version of the camry and I clicked on the link you gave me and all it did was show me images of compressors and some transmission sensors and other misc. images but no images of the rpm/ compressor sensor we've talked about. so it wasent really any help. What I can do is go to the junk yard again and find a camry with the compressor still intact and remove the rpm sensor or get a couple of them and install it on my car and see if it resolves the issue. Its better than buying a used compressor and cheaper and since the ones at the auto parts store don't come equipped with the sensor already on the compressors its senseless to get one there and anyway I wont loose any Freon and it will be hopefully quicker and easier to do. let me know what you think. also if we could Skype I would have to use my sons smart phone since I don't have one. The problem is this car is not actually mine but my sisters and she dosent live close plus I have to work around her schedule and I have to get her permission to pay the extra 15.00 to skype with you and it has to be when she is available which wont be until next Monday the 15th in the morning so if the sensor replacement I will attempt to do that I get from the junk yard does not work will you be available next Monday morning around 10-10.30 am eastern time to Skype if she oks the 15.00 charge? please let me know. thanks
Expert:  Peter Bagley replied 11 months ago.

that would be the smarter move is to get a used sensor or complete compressor what ever is easier for you . , I know that link was a little miss leading but just wanted to show you that there is such a thing as a A/C compressor speed sensor lol, it's job is to match the engine rpm to that of the compressor signal to send to the amplifier and then the amplifier can do it's job. hope this helps and hold off on that extra $15 until you tried a different sensor OK. good luck.

Customer: replied 11 months ago.
alright so at this point until I see my sister and her car, it may be next week before I can follow up with you on the outcome from this rpm sensor replacement. I have a u pull it yard close to me so I can scout on my own the camrys that have compressors with the sensor and take off the sensor and maybe ill get another one just in case. by the way is this part a common failure on this generation of camrys? I know its a dinosaur but it has low miles for the age of it and drives fine. please let me know thanks.
Expert:  Peter Bagley replied 11 months ago.

well between the amplifier and speed sensor it's by far the most common part failure , now that's assuming all those other things I mentioned before check out properly those are the only two left that can cause it.

Customer: replied 11 months ago.
ok so if we need to Skype can we next Monday in the morning maybe around 11am-12 ish eastern time zone
Expert:  Peter Bagley replied 11 months ago.

Before we skype and charge more try that speed sensor and check it's connections first. good day.

Customer: replied 11 months ago.
will do peter my sister is coming over Monday morning and I will hopefully find a good sensor at the u pull yard. thanks, dean
Expert:  Peter Bagley replied 11 months ago.

just checking your progress and if you tried that speed sensor compressor yet?

Customer: replied 11 months ago.
hi peter I will do it tomorrow when my sister can come over
Expert:  Peter Bagley replied 11 months ago.

very well and good luck , if you need any more assistance let me know , happy to help.

Customer: replied 11 months ago.
hi peter its dean i started to remove that rpm sensor from my sisters car and the compressor started pouring out oil so i guess that sensor is in the oil sump so am i going to loose alot of oil or all of it in the compressor because im going to have to buy oil charge at the parts store to replenish it and im concerned about running that compressor without any oil in it to recharge it with oil if it all drains out when i remove the sensor. the only other thing i can do is unbolt the compressor with the lines still hooked up and tilt it so the sensor is not facing the bottom and try to remove it that way without loosing much oil so let me know
Expert:  Peter Bagley replied 11 months ago.

Hi Dean not knowing how much you lost , Here is the oil capasity for the system mineral oil for R12 Freon 8.75 ounces. If it has been retro fitted with R34 refriferent then you needto use the proper oil.

Customer: replied 11 months ago.
hi peter its 134a and i didn't remove the sensor completely yet because oil started comming and i didnt loose much out so if i get the oil charge can which are 3 oz cans ill put it in that way with my ac gauge. im hoping the compressor will not be harmed by running it at first with less oil in it to recharge it with oil
Customer: replied 11 months ago.
i peter i removed that sensor and all the freon came out so now i have to buy more freon and i dont have a way to vacuume it down so i have to take my chances that it will blow cold when i recharge it. i did block off the port where the sensor goes but i have one chance to try another sensor to see if that works so not happy about this and i was hoping you were right about not loosing the freon when i removed the sensor.
Expert:  Peter Bagley replied 11 months ago.

My apologies , I assumed that you were aware that removing the speed sensor would do that, forgive me for assuming that, but either way if you got a complete used compressor or just the sensor you still needed to e vac the system before charging because when the system is open to the air it draws in moisture which can cause internal freeze up and troubles.when you just top it up you don't need to because your not allowing moisture into the system. Also without a vacuum you won't get a complete charge even though the Gauge may show good pressure it still may not have enough refrigerant in the system., you can try it but be forewarned. Also you can lubricate the sensor seal with a little of the compressor oil that save s any contamination getting into the system. If you can estimate how much oil came out you may not need the whole amount as i stated that's from empty. Again my apologies , some times just texting procedures on here I get ahead of myself.

Customer: replied 11 months ago.
hi peter I agree with all you said but I didn't have a choice since I didn't have a vacuum pump. I did block the hole where the sensor went until I could put the used one in there. so I did put it in and by the way I had the same issue on the car at the junk yard because it had a full charge of Freon in it too. so I installed the used sensor the got the compressor running added the Freon and 3 oz oil charge and amazingly it worked! the ac blows fairly cold and the compressor stays running and cycles off. so my sister is happy and I thank you very much. I would of never imagined that sensor could cause a blinking ac light. so much for youtube and Toyota blogs. also I have another ac question I wanted to ask. its on a 2007 civic and its been like this for 2 months. the ac blows cool not cold and takes a while to cool the car. the Freon level is fine the belt is tight and the pressures read at idle low side 40-45 psi and high side 210-230 psi but at 200 rpm the low side goes to 18-20 psi and high side 375-395 psi or higher. I think the expansion valve is bad so what do you think?
Expert:  Peter Bagley replied 11 months ago.

mmm they are actually high on both sides but way off charts on pressure side.has any one topped the system up recently?perhaps over charged. the pressures should be low side--25-35psi high side - 175-185

Customer: replied 11 months ago.
no one has topped it off with freon when it started acting this way originally but i did recently add some freon but it didn't help and the high side started climbing over 400 psi at 2000 rpm while the low side was at 20 psi so i let some out and it got a little better and cooled a little better but not blowing as cold as it should. i don't know if letting more freon out will help because the low side will probablly drop even lower so i'm still guessing the expansion valve isn't regulating the pressures properly
Expert:  Peter Bagley replied 11 months ago.

This is a different car and question so I will require additional time, thank you.

Customer: replied 11 months ago.
is that to say that in order to answer this question on my 07 civic i would have to pay 10.00 more and if so for how long can we talk about this car?
Expert:  Peter Bagley replied 11 months ago.

Well this is not only a different question but different car so yes and we can take it as far as the other one if you agree.

Customer: replied 11 months ago.
hi peter i want to continue our discussion on my 07 honda civic. I will guess that in the end your going to give me the same answer i already know that my ac problem is the expansion valve, but i'm willing to pay the 10.00 to be sure about since you were spot on with that rpm sensor on the 96 camry
Expert:  Peter Bagley replied 11 months ago.

well if you look back at the pressures what you gave me your high side is excessive and low side below normal as to the ones for that vehicle, that indicates a blockage at the expansion valve . if it were equal on both sides it would be an internal leak in the compressor and that's not what your experiencing. and it is putting out good pressure even though high so the compressor is working.so that my friend leaves just one thing, the expansion valve. advise you to replace it soon because it can cause damage to the compressor. You can try an A/C flush if you have a shop that is capable of doing that and it's just clogged but that's up to you.

Customer: replied 11 months ago.
ok peter i did check the pressures again yesterday and at idle it was 42-46psi on low side and 285 psi hi side but at 2000 rpm the low side went to 22-25 psi and hi side went to 400 psi and at 2500 rpm low side was 20 psi and high side went to 390-420 psi and again blowing moderately cool out of the vents not cold even though we have 90 plus degree days tight now. so this sounds like the expansion valve so me and a mechanic friend were going to do the work because he has a vacuum pump and a refrigrant recovery machine and i will replace the desiccant for the drier too. thanks for your help. i will keep you on record if i need automotive help again
Expert:  Peter Bagley replied 11 months ago.

thank you and glad your happy.