A/C Problem

[TheDeal526]

1993 Buick LeSabre Custom 3.8

I was just wondering when excatly is the A/C compressor suppose to turn on. I press every vent control button in my car and the compressor does not kick in. I'm sure I have some type of A/C problem but I would still like to know for future reference what turns the A/C on since there is no button that says "A/C".

[HotZ28]

The compressor will not cycle if the outside temperature is 55 deg or colder no matter what button you select or how low you set the temp display. When temps are above 55 deg. the compressor will only cycle on as needed to maintain the set point on the display. If you have ACC (auto climate control) the compressor will cycle if the "Auto or Defrost" buttons are selected and again, only if the set point on the display is lower than the cabin temperature, or a very humid condition is detected.

[Bassasasin]

Also good to note.. if you have lost your refridgerant.. the compresor wont kick in..
Theres a sensor that knows theres a bit of pressure in the lines and will allow the compressor to run.
You may just need a little refridgerant..

Good Luck

[TheDeal526]

this car uses r12 refridgerant. if im low on refridgerant, wouldnt that mean i have a leak somewhere? i know before i purchased this car it wasnt driven for quit sometime. would the car lose refridgerant from not being driven?

[HotZ28]

A very small refrigerant leak over a period of time, could cause the system to drop below the threshold, where the pressure switch senses low refrigerant and the compressor will not cycle. The compressor seals require refrigerant & oil circulation in order to maintain flexibility. If they sit too long without oil circulation, the seals can become dry and leaks can start. What system do you have, ACC or standard? If you have the ACC system, the 1993 model display, will give a fault code for low Freon. When you first turn on the ignition switch, the temperature display will flash for two minutes, indicating a fault code in present.

[TheDeal526]

i have the standard system, no display at all. i was just cusious because every car i had in the past has always had a button that said "a/c" and or "a/c max". I do have a button that says "max", which i assume is the same as "a/c max". I also have buttons that says "norm" and "vent".

Does anyone have any idea what the difference between "norm" and "vent" is?

Also, if the seals in my compressor are dry and are leaking, can i just replace the seals, or would it be a good idea to just replace the compressor? Are there seals in the lines that I may need to replace also? I'll get a leak detection test done during the warmer months, but i would just like a heads up before i do that.

[TheDeal526]

just curious, with the A/C system not running for such a long time, when it finally does come time to make repairs to the system, what should i focus on? when the warmer months come, the first thing i wanna do is have the entire A/C system checked for leaks. But is there anything else i should focus on?

[HotZ28]

On a car of this age and still using R12 refrigerant, it would be better to evacuate the system first, to remove the old R12. After evacuation, have the system completely flushed, to remove all of the old mineral oil. Install a new orifice tube and accumulator along with a retro fitting kit for R134a, and evacuate the system again to boil off any residual moisture and to check for leaks. You can add the new POA oil while the system is apart, or after the system has been evacuated. After the system is secure and no leaks detected, proceed with charging the system with R134a. Most AC shops charge 150-200 bucks for this procedure. The accumulator and orifice screen are mandatory replacements and only cost about 45 bucks for both.
(Do not allow anyone to do this procedure without replacing both)!!

BTW; don't wait until the lines start getting long at the AC shops! You should try to have everything done by April!