a/c problems

[robby269]

hi everyone..a question for you gurus, my a/c only works occassionally, great when it does come on, i checked pressure switch and that isn't problem, compressor won't come on, i have 1989 lxi , can someone tell me where compressor clutch relay and delay relay are located? haynes book said clutch relay on left inner fender...not there on mine, and a/c delay relay behind glove box..not there on mine either..help..it's gonna be 90 tomorrow..thank you all

[nswst8]

If your compressor is cycling, then you ned to check your pressures. It sounds like you have low freon. the low pressuse switch is on the receiver dryier

[LX-incredible]

Yes, check your charge. Those things rarely go bad. The delay module is attached to the bottom of the blower housing. There is also a temp switch on the side of the evaporator housing, which shuts the compressor off when evaporator gets too cold

[robby269]

i have checked freon and added to it, it works very well when it does run the problem is compressor clutch frequently doesn't pull in..when it does air is very cold

[robby269]

my compressor is not cycling and that's why i want to know where compressor relay is located, compressor only comes on sometimes but when it does it is cold i do have a good charge of freon

[robby269]

i did check pressure switch and it is ok , second radiator fan comes on when i turn on a/c but compressor only comes on occassionally

[LX-incredible]

Also make the cooling system is properly functioning. If the engine is overheating the ecu will not let the compressor come on to overheat further (at least on the fuel injected models).

[LX-incredible]

i did check pressure switch and it is ok , second radiator fan comes on when i turn on a/c but compressor only comes on occassionally

Is the main fan coming on as well?

[robby269]

yes main fan is coming on and i have good mix of antifreeze and it is not overheating it just seems like i have a bad connection to compressor, when compressor does come on it cools car very well it has gotten worse lately about not coming on

[robby269]

do you know where compressor clutch relay is located on '89 lxi?

[LX-incredible]

my compressor is not cycling and that's why i want to know where compressor relay is located, compressor only comes on sometimes but when it does it is cold i do have a good charge of freon

Some systems will be their coldest at idle with a low charge, but the pressures will drop once some air starts flowing over the radiator and RPM is increased. I remember it being around 10-15 psi on the low side where the switch kills it.

What are your high/low pressures?

[LX-incredible]

do you know where compressor clutch relay is located on '89 lxi?

Behind the left headlight, next to the radiator.

[robby269]

i don't have actual psi guage, just the red and green gage that came with hose on can, i had low freon and air was only mediocre cool with compressor clutch pulled in , i added 2 bottles of freon with temp on gage set at 80 degrees and gage was in green area which was supposed to mean a good charge of freon, it worked great for about 2 months but now compressor hardly pulls in clutch but when it does even tooling down hiway at 80 mph air is very cold, i drive 100 miles one way to work and last couple of weeks clutch only seems to pull in when it feels like it , works great when it does, although not so well at idle

[robby269]

since i don't have actual gage set i'm hesitant to add more freon as i don't want to overcharge it, when clutch pulls in it is very cool i usually don't run on hi when it works, even with fresh air not recirc it cools very well

[robby269]

thanks for all replys , i'll look again for clutch relay i thought i looked thoroughly last nite but obviously i must have missed it..thank you for all your help

[nswst8]

What type of freon are you using? I don't thinks its R12. so it must be R134a and you should only be using no more than 20-24 oz for a fully charged system. The sweet spot is somewhere in that zone.

You said you used 2 can of how many ounces? Was your clutch cycling before you put in the 2 cans. This means you had freon in it to begin with, so you are probably over charged. R134a operates at higher pressure than R12.

You really need to get some pressures on the system. Otherwise you are just going to blow out your seals.

[nswst8]

Basic Charging Procedures
REFRIGERANT CHARGING PROCEDURE IN AUTOMOTIVE A/C SYSTEMS

We recommend reading this procedure completely before charging. You may need information before charging you want to keep handy. Have this procedure with you while charging. Although it can be done by a single person, we recommend having a helper around.

This procedure outlines the steps to perform a complete charge. These steps are not to be used to refill or make partial charges. Toping off requires system parameters monitoring and knowledge, specially in R134a-based system. Excessive gas will harm your system and will keep it from cooling properly. MORE REFRIGERANT DOES NOT MEAN COLDER TEMPERATURES

CHARGING IN GAS OR LIQUID - Please read step 10

Do not use the sightglass (if so equipped) in R134a-based systems as if were R-12 based.

SPECIAL EQUIPMENT REQUIRED

1) Vacuum pump

2) Gauges (R12 or R134a)

3) Service port adapter (as required in most R12-based systems) R134a systems do not require adapters other than the couplers in your gauges in the majority of applications

4) Refrigerant gas (R12 or R134a)

5) Optional: 2-3 ounces of specified oil.

**************

1. Make sure what is the required amount of gas. From factory, all systems have a decal under the hood that give the data. If the decal is missing or you are not sure, please specify make, model, and the type of refrigerant used and whether your system is a factory or an after market unit here. It is very important to know if your system has oil. Oil starvation is the main reason of compressor failure. Oil can be added to the system in two ways: with oil injectors or through the low side port under vacuum. The procedure to add oil through vacuum is described here. Some refrigerant charge and other useful specifications are provided here.

2. Connect both blue and red gauge hoses to the system's service ports. The discharge port (red hose) is located somewhere between the compressor and expansion device, either before the condenser or after it. In R134a systems, the port is the thicker of both, while in R12 systems is the thinner one. In some aftermarket systems, the port is located in the back of the compressor. If your ports are located in the compressor, the low side is marked by an "S" and the high side by an "H". Port caps have an "L" for low or "H" for high.

3. Open both gauge valves. Connect the common hose (yellow one) to the vacuum pump. Make sure both gauge needles are zeroed down. Needle is adjusted by turning a fine screw inside the dial. You must remove the plastic lens to do this.

4. Turn the pump on. You'll notice that both gauge readings begin to drop. The blue gauge's needle will even dip into negative values. The desired low side reading should be less than -25, while the high side will remain at 0.

5. After approximately 5 minutes, close both gauge valves. Turn the pump off, and observe the needles. Any movement will indicate vacuum loss. The faster the movement, the greater the loss. If after two minutes you don't see any needle movement, open both valves, turn the pump on, and continue vacuum for not less than 30 minutes. Close both valves then turn the pump off.

6. Get ready to charge. Have the necessary refrigerant amount handy. Cans make charging easier and more precise unless you have a charging cylinder or a precision scale.

7. Disconnect the yellow hose from the vacuum pump and connect it to the can tap or charging cylinder valve. You can charge in two ways: liquid (can upside down) or gas. Liquid charging is a lot faster but not recommended unless you extreme care or have experience. Traditional (gas) charging is slower but safer.

8. Once you've decided, and with the can or container connected, unscrew the top yellow hose connection (at the gauges) allowing refrigerant to escape for a couple of seconds. This will purge the air out of the hoses so you make sure that all you dispense is refrigerant. You can do this venting in liquid form so you can see when a fine, steady stream of refrigerant escapes indicating that all the air is gone from the hose. Don't breathe refrigerant and don't charge in a flammable environment.

9. "Flood" the system with liquid refrigerant (can upside down) by opening the red valve (high side) until it won't take anymore. Close the red valve. Jump the low pressure cycling switch (if so equipped). If you don't know what this is or where it is, ask for help here.

10. Turn the engine on. Turn the A/C into MAX on its third or higher blower speed. You'll note that both gauge readings are now positive. The red gauge should read between 100 and 150, while the blue gauge between 5 and 15. If you are charging with cans, don't forget to purge air out the hose after hooking a new can as described in step 8 above. Now, charge will continue through the low (blue) side (see note below) . If you haven't jumpered any switch (you don't have to), you'll notice the compressor cycling frequently on and off. That is normal. The cycling will disappear as you dispense more refrigerant. The only disadvantage of frequent compressor cycling is that charge will take longer. Needles will move up and down with every cycle. This is normal. Do not jump any switch unless you are absolutely certain!.

WARNING: DANGER

NEVER OPEN THE RED VALVE WHILE CHARGING. The red valve is to be opened only during pre-charge, vacuum, or when a system is evacuated. Its function is keeping an eye on the high side only. It must be closed at all times. If you have any doubts, wait until you receive information. Severe injury or death may occur. Remember: ALWAYS wear safety goggles. NEVER charge your system in a closed environment.

GAS OR LIQUID CHARGING?

There are two ways to charge: gas (can or cylinder up), or liquid (can or cylinder upside down). A compressor is designed to compress gas. Direct liquid charge will harm the compressor if suction pressure is not controlled. Liquid charging is faster, yet is riskier. Liquid charging should be made by professionals or under supervision. Liquid charging can be done if the suction port is away from the compressor (some compressors have the suction valve in its body).

Liquid charging can be done never exceeding a 50 PSI suction pressure. If you can't control it, charge in gas form. In cooler weather, cans may freeze. You may immerse them in water and shake them while charging.

11. Once about 2/3 of the charge has been dispensed into the system, spray water in the condenser to optimize heat exchange and speed the process. When you get the condenser wet, vent temperature is likely to raise. This is normal. You'll also note pressure drop in both gauges.

12. Once the specified amount has been dispensed, close the blue valve. Let the system run for a minute. Turn the A/C off and then the engine. Wait another minute and disconnect the couplers from the service ports. Disconnect the low side first. If you jumpered a switch, reconnect it too.

Optimum cooling performance is attained after 10 minutes of operation. Our own acceptance criteria is at least 50°F in the center vent to the driver side at idle after 10 minutes or less. Remember: cooling increases while the vehicle is in motion.

VERY IMPORTANT

Due to the physical properties and chemical composition, R134a and R12 charging amounts are different. Never, if you are retrofitting, charge the same or specified amount of R12 with R134a. If in doubt, please e-mail us here. Do not use this procedure if you are using any other refrigerant. This is just for R12 or R134a. Although procedures and parameters may be similar, we do not use nor recommend alternative refrigerants.

HOW TO DETERMINE OPERATING PRESSURES

Every vehicle has its own operation parameters specification. Depending on whether or not the vehicle has a factory or an after market system, and whether it was retrofitted or is still original, among others. There is no established calculation to determine the exact operating pressures.

The low pressure (blue gauge) should be 35 or less at idle, regardless of the type of gas. Only if you're running a dual system, the low pressure may be between 45 and 50 at idle.

The high pressure, for starters, is directly related to ambient temperature: the higher the temperature, the higher the higher the pressure.

Bear in mind that dispensing a complete charge without lowering the pressures with water will result in higher readings. This is normal, and that is why you should spray water in the condenser at 2/3rds of the charge or once you have completed it. You'll note an immediate pressure drop when you spray water in the condenser.

To obtain a ballpark high side value, multiply ambient temperature by 2.2 if you have an R12 system. If you have a factory R134a system, use 2.3. To convert °C to °F, use this formula: °C X 1.8 + 32.

Remember: this is only a ballpark. If in doubt, we have factory charts to help you determine the correct pressures. Please have your vehicle's make, model, refrigerant type, and year and click here.

Factors like a an obstructed or very dirty radiator and condenser, weak or inoperative fan clutch, weak or inoperative radiator fan(s), either electric or mechanical, will make pressures go up and impair cooling, even in mild days.

[Dr_Snooz]

I agree with nswst8. You've overcharged your system. Buy a proper set of gauges and get a good reading on your pressures. The ones from Harbor Freight for $40 work great.

[robby269]

thank you phil i used 134a that's what kind of system in car they were the small walmart cans , i will check can size tonite, i will also invest in a set of harbor freight gages, the a/c woked last nite on the way home just fine.. but tonite it may not work at all thank you for the very good advice, when i get gages and test per your procedure i'll repost results

[robby269]

i checked the cans last nite they were 12 oz,thanks lx-incredible i found the clutch relay and that was the problem it was loose and had power steering fluid on it from a leak in ps hose..i've got a new hose to put on..i will still get gages and check pressure per post here..i sincerely appreciate everyone's advice..a/c worked great this am..great site..these are awesome cars if you know how to work on them