My A/C won't blow cold air even after I turned it on. The engine idles at a higher RPM even though the compressor's clutch won't engage. I've checked the A/C fuse and it's still in good condition. The blower is fine and the green A/C turns on whenever I press it, but just won't blow cold air. I then checked the compressor to see if it turns on, but the center of the pulley doesn't spin when A/C is on. I don't know whether the compressor is broken or if there's a leak (how do I easily check for one?), or if a relay/fuse is broken. I believe it uses R12 (has Schrader valves at lines). Anyone can help me with my problem? It's a 1988 1.6 carb Corolla
First check to be sure the electrical connector at compressor is fully seated. Other than that you have most likely lost the charge of freon and the pressure switch is preventing the compressor from turning on to keep it from being damaged. The original fill was R12 which is quite costly as not being produced any longer. You need to take this to a shop where they have the equip to verify the state of charge, find where the leak originated, replace the part and if not already done retrofit to R134 and then pull a vac on system and refill. Not really a DIY project because you need access to a gauge set, pump to pull a vac on system etc.
If the ac clutch doesn't engage but the idle still goes up when you turn on the ac, then check the ac relay if it's working. It's located in the smaller fusebox from within the engine bay, the one nearest to the battery.
First check to be sure the electrical connector at compressor is fully seated. Other than that you have most likely lost the charge of freon and the pressure switch is preventing the compressor from turning on to keep it from being damaged. The original fill was R12 which is quite costly as not being produced any longer. You need to take this to a shop where they have the equip to verify the state of charge, find where the leak originated, replace the part and if not already done retrofit to R134 and then pull a vac on system and refill. Not really a DIY project because you need access to a gauge set, pump to pull a vac on system etc.
What connection does the compressor have to the electrical system? I only see the 12v cable(right next to the alternator) and another black-sleeved cable that plugs to the compressor, I think. I'll take some pictures in a few hours. Also, how do I know if I have a leak without taking it to a shop?
Quote:
Originally Posted by darien
If the ac clutch doesn't engage but the idle still goes up when you turn on the ac, then check the ac relay if it's working. It's located in the smaller fusebox from within the engine bay, the one nearest to the battery.
How do I check if the relay is broken? Do I jump the compressor at the fuse box?
The electrical connections you refer to are the ones to check. Make sure they are fully plugged in. The only way to check for and determine where a leak is would be to add dye and check with a black light . Also look visually because sometimes where there is a leak there will be an oily residue. The condenser in front of radiator can get hit by road debris. Connections on the metal lines can also leak.To add the dye you need to have the compressor functional which doesn't help you. For the relay I would buy another if you want to check it or if there is another relay in the fuse block with the same number try swapping them out and then buy one.Can't tell you which terminals to jumper and frankly don't recommend it or you will have other problems. I really think you have somehow lost freon to the extent that the pressure switch is preventing compressor clutch from engaging.
I've jumped the compressor and found out it spins. The relay is not broken as I've swapped it with another one nearby and it works. I've checked the cable connections, the black sleeved cable seems plugged in and the white plastic connector above/next to the alternator seems good.
I've checked all the metal lines all the way from the firewall of the passenger side all the way to the condenser in front of the radiator, and have found no leak(assuming there will be oil at the leaking point). One of the high/low pressure valve (I don't know which is what) has air bubbling at the top of the Schrader valve. I put a little drop of water in there and see air bubble coming up very slowly. Here's a picture (not taken by me, another member's pic) of the said valve
EDIT: Actually, air bubble only come up occasionally, not all the time.
First you need to find out if there is ANY R12 freon in the system. You already know where the Schraeder valve with the Red cap is, now find the Schraeder valve with the black cap and unscrew it. Using the tip of a pen, pencil or toothpick, depress the valve slighting to see if freon hisses out. If so, that is a good sign the system has a partial charge of R12 and simply needs more R12 to get the compressor to run again (assuming compressor is not seized).
Attach the can tap valve to the can (wear goggles in case of an accident that causes freon to spurt -20 degrees F refrigerant into your eyes). Screw the charging hose onto the BLACK (never the red) Schraeder valve and open the can tap valve so that gaseous freon flows into the cars AC system (can must be held upright). Keep the can submerged in 110 degree F water to force gaseous freon into the system. It will take many minutes but eventually at least half the can will go into the system if you keep it at around 110 (don't go hotter or the can could burst and blind you for life)
Now that the system has more freon in it, start engine and push AC button to see if the compressor will now run and deliver cooling. If so, then the main reason the AC system wasn't working is because the former owner let the refrigerant charge get so low that system pressure got real low and prevented the magnetic clutch from activating when the AC button was depressed.
First you need to find out if there is ANY R12 freon in the system. You already know where the Schraeder valve with the Red cap is, now find the Schraeder valve with the black cap and unscrew it. Using the tip of a pen, pencil or toothpick, depress the valve slighting to see if freon hisses out. If so, that is a good sign the system has a partial charge of R12 and simply needs more R12 to get the compressor to run again (assuming compressor is not seized).
Attach the can tap valve to the can (wear goggles in case of an accident that causes freon to spurt -20 degrees F refrigerant into your eyes). Screw the charging hose onto the BLACK (never the red) Schraeder valve and open the can tap valve so that gaseous freon flows into the cars AC system (can must be held upright). Keep the can submerged in 110 degree F water to force gaseous freon into the system. It will take many minutes but eventually at least half the can will go into the system if you keep it at around 110 (don't go hotter or the can could burst and blind you for life)
Now that the system has more freon in it, start engine and push AC button to see if the compressor will now run and deliver cooling. If so, then the main reason the AC system wasn't working is because the former owner let the refrigerant charge get so low that system pressure got real low and prevented the magnetic clutch from activating when the AC button was depressed.
Thanks for the help, but just to make sure...How do I know if it's really R12 and not R134a? The original owner said he serviced the A/C system before (this was a year ago) and I assume the shop told him to convert to R134a, but it has the Schrader valves (and I believe R134a uses different valves). Is it possible that the shop just evacuated the R12 and pumped in R134a but kept the same valves?
Thanks for the help, but just to make sure...How do I know if it's really R12 and not R134a? The original owner said he serviced the A/C system before (this was a year ago) and I assume the shop told him to convert to R134a, but it has the Schrader valves (and I believe R134a uses different valves). Is it possible that the shop just evacuated the R12 and pumped in R134a but kept the same valves?
Legally the shop would have had to install different valves in order to install R134a. The shop might have also used an R12 substitute like Freeze 12 or HotShot but again I think legally the shop would have to install a sticker showing what was added.
There's really no way of knowing for sure if there is no sticker or other evidence. Genuine R12 delivers superior system performance and durability, but shops hate it because they know they can make much more money on conversions.
Legally the shop would have had to install different valves in order to install R134a. The shop might have also used an R12 substitute like Freeze 12 or HotShot but again I think legally the shop would have to install a sticker showing what was added.
There's really no way of knowing for sure if there is no sticker or other evidence. Genuine R12 delivers superior system performance and durability, but shops hate it because they know they can make much more money on conversions.
I was wondering, since R12 is expensive, is it possible that the shop pump barely minimum pressure just so that the compressor would turn on, and the after a year of losing pressure, the original owner would have to go back to service the A/C due to lost of pressure?
I was wondering, since R12 is expensive, is it possible that the shop pump barely minimum pressure just so that the compressor would turn on, and the after a year of losing pressure, the original owner would have to go back to service the A/C due to lost of pressure?
Yes, possible. Also possible the system has a small leak and needs partial refilling every 6 months or so. The cost of partial refilling every 6 months ($20-30 if you do it) is alot less than the cost of labor and supplies for a shop to evacuate the system, fix the leak, replace the receiver-drier and recharge ($300).
Yes, possible. Also possible the system has a small leak and needs partial refilling every 6 months or so. The cost of partial refilling every 6 months ($20-30 if you do it) is alot less than the cost of labor and supplies for a shop to evacuate the system, fix the leak, replace the receiver-drier and recharge ($300).
I'm going to get some R12 cans and try filling it up. Thanks for the help!
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