QuestionDear Expert: Unwilling to spend more big bucks on a 1992 Toyota Camry, 4 cyl LE model that has become a money pit, I would like some info on servicing the a/c system since there is no cold air blowing. Where is the low side port? I can't find the accumulator. Does the car have an expansion valve system? Although the compressor was supposedly replaced in Aug 2005, I also would like to determine if the compressor is working. The info I gleaned online leads me to believe that a compressor will not work if the low pressure switch is faulty or the compressor is void of refrigerant(in this case R-12.) If I jump the wires in the connector to the low pressure switch(and would you elaborate on that) and the compressor kicks in, does that eliminate the lack of refrigerant as a reason for the non-functioning compressor and I can pretty much target the low pressure switch as being bad? Also where does one obtain info as to how much refrigerant and oil a specific system requires? A helpful response would be greatly appreciated. Thank you.
AnswerEdward,
I understand completely, I have a money pit myself. I will try to hit all of your questions, but should I lookover one I will apologize now.
As for the low side A/C port... You will find this attached directly to your low side refrigerant line. Typically this is located on the passenger side of the engine compartment, near the strut tower. It may have a black or blue cap on it. If you should see two ports in the same general area, the low side port is the smaller in diameter.
Expansion valve. Where many manufacturers have gone to the orifice tube type of metering device (cost being the main reason) your Camry does use an expansion valve. This is located inside the evaporator/heater housing inside the passenger compartment of the car. In order to service this is would it involve the removal of this housing. But... the expansion valve systems have always been a better setup and are rarely found to be the fault of the problem.
You are absolutely right. The low pressure switch is wired in series with the compressor so that should the contacts open, it will disengage the compressor clutch. What would cause these contacts to open. The first would be a low refrigerant charge. Your low pressure switch (or clutch cycling switch as some refer to it as) reacts to the pressure inside the system, as long as the system low side pressure does not fall below roughly 22 psig, the contacts within the switch will close. As soon as it falls below this point, they open up, in turn protecting the compressor from operating in a low pressure situation which could cause extensive damage to it and other components inthe system. And yes, as with everything, these do go bad, but not as frequently as you would believe.
Jumping it. First, the camry used what is called a dual pressure switch as well as a high pressure switch in he system. In order to jump the dual pressure switch. Locate it. It is on or near your receiver/drier. This is typically a black in color canister with two lines protruding from the top/sides of it. It will have 2 switches on it. Unplug switch on the left. (Though if you jump them both it will not harm anything) With your car in the run position with the engine off, and the a/c switch on... take a small insulated piece of wire and jump the terminals inside the harness plug. You should hear the clutch engage. (Sounds like a "snap") If it does, this tends to lead us to the conclusion that you have a low refrigerant charge, or the pressure switch is bad. (I know... all of this and we haven't gotten anywhere right?) Typically this will be a low refrigerant charge though. In order to check the switch itself, you will need a set of gauges hooked to the system as you check for continuity across the terminals. If you read less than 30 psig or more than 384 psig on your gauges, you should NOT have continuity between the terminals. More than 33psig and less than 299 psig, you should have continuity.
But before you go through all of this, check your refrigerant charge. Again, I believe that you will find it to be low and needs to be recharged. But keep in mind, if the refrigerant is low, that means there is definately a leak in the system that should be found and repaired. A/C systems are sealed systems and should never need to be charged.(Much like your refrigerator in the house)
As for where to find the charge amount and amount of oil a system requires... this should be located on one of the labels under the hood of the car. It is often times on the same label as the belt routing diagram and spark plug gap. This will be found on either the fan shroud, radiator bracket, or bottom side of the hood itself.
On a bad note... being that your system is R-12, you will not be able to charge it yourself, and alot of service shops will not be able to either. You wont be able to, because it is illegal to sell to an individual that is not certified under section 609 of the Federal CAA. Most shops no longer deal with it because it is being phased out due to its ozone depleting properties and the stock of it nationwide is nowhere near where it should be. You will also find it to be alot more expensive than a refrigerant such as R134a, because of this reason. I believe the average cost is around 60 dollars per pound these days. With that in mind, you may want to consider this a good time to retro-fit your car to R134a.
Thank you for the question, I hope I was of some assistance. If I can do anything further during this process, or in the future, please do not hesitate to ask. If you found this response to be of some assistance, please remember to rate this answer. Thanks again and good luck in everything.
