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Discussion Starter #1
My 1984 Cadillac Coupe deville A/c turns on and off all the time while driving and the off button does not respond.Does anybody know what the problem could be?
 

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When the A/C turns on & off repeatidly it's called short cycling.
The most common cause is low on freon.
It was R-12 in 84', unless it's been converted to R-134A.

The A/C compressor shuts off because the low side pressure is too low.
If it ran with to low of a pressure the tempiture would be too cold and the evaporator would ice up.
No air would flow past the ice so while being technically colder, the result out the vents is not so good.

Without a gauge set (high & low A/C pressure gauges) your only guessing.
It could be also cutting out because pressure is too high.
Hooking up a gauge set only takes a minuite & can answer many questions and sometimes indicate additional problems such as a bad compressor.
Stores sell freon with a low pressure gauge. I hate that as it doesn't alert you to damaging or dangerous conditions.

Before the whole freon kills the ozone & patent is ending on Dupont R-12 thing A/C systems weren't sealed as well as they are now. Leak detectors wereen't as sensitive. Even if the leak was known, sometimes it made more financial sense to just add a lb of refrigerant every spring for maybe $60 vs replace the evaporator for $500.

Back in the 80's to early 90's a 12 oz can of R-12 cost about $1.
When charging the car sometimes you didn't need the full can or didn't want to wait for it to empty.
Releasing it from a quick side can tap would launch the can in the air.

You could loose a few ounces in each of the hoses if they didn't have a check valve or manual valve, most didn't.
And a few more unscrewing the hose connections, unless the shrader valve froze open, that would suck.
Hard to get every oz out of 12 oz cans.
Again the cars & tools weren't designed to treat every ounce as a valuable commodity or danger to the enviroment as some say.
For that reason it would take more cans than the car holds in ounces.

At 1 time cans were selling for $50.
It can still be had on Ebay for a bit less now.
But if you don't have the A/C equipment you need to make sure your hoses connect to R-12.

By the question I would recomend taking it to a repair shop.
I would imagine not too many shops mess with R-12 anymore & it'll be converted to R-134a.
That's a different debate which it better.

Don't know anything about the A/C control (programmer) but would guess it's just a worn out off button.
 

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95 FWB 81SDV 96 FWB 94 Fleetwood
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It sounds like you have two problems. If it is short cycling , going on for 5-10 seconds and then off, I would guess it is low on freon . As for not responding to controls is another problem.
 

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Discussion Starter #4
It sounds like you have two problems. If it is short cycling , going on for 5-10 seconds and then off, I would guess it is low on freon . As for not responding to controls is another problem.
Thank you I appreciate your help.
 

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Discussion Starter #5
When the A/C turns on & off repeatidly it's called short cycling.
The most common cause is low on freon.
It was R-12 in 84', unless it's been converted to R-134A.

The A/C compressor shuts off because the low side pressure is too low.
If it ran with to low of a pressure the tempiture would be too cold and the evaporator would ice up.
No air would flow past the ice so while being technically colder, the result out the vents is not so good.

Without a gauge set (high & low A/C pressure gauges) your only guessing.
It could be also cutting out because pressure is too high.
Hooking up a gauge set only takes a minuite & can answer many questions and sometimes indicate additional problems such as a bad compressor.
Stores sell freon with a low pressure gauge. I hate that as it doesn't alert you to damaging or dangerous conditions.

Before the whole freon kills the ozone & patent is ending on Dupont R-12 thing A/C systems weren't sealed as well as they are now. Leak detectors wereen't as sensitive. Even if the leak was known, sometimes it made more financial sense to just add a lb of refrigerant every spring for maybe $60 vs replace the evaporator for $500.

Back in the 80's to early 90's a 12 oz can of R-12 cost about $1.
When charging the car sometimes you didn't need the full can or didn't want to wait for it to empty.
Releasing it from a quick side can tap would launch the can in the air.

You could loose a few ounces in each of the hoses if they didn't have a check valve or manual valve, most didn't.
And a few more unscrewing the hose connections, unless the shrader valve froze open, that would suck.
Hard to get every oz out of 12 oz cans.
Again the cars & tools weren't designed to treat every ounce as a valuable commodity or danger to the enviroment as some say.
For that reason it would take more cans than the car holds in ounces.

At 1 time cans were selling for $50.
It can still be had on Ebay for a bit less now.
But if you don't have the A/C equipment you need to make sure your hoses connect to R-12.

By the question I would recomend taking it to a repair shop.
I would imagine not too many shops mess with R-12 anymore & it'll be converted to R-134a.
That's a different debate which it better.

Don't know anything about the A/C control (programmer) but would guess it's just a worn out off button.
Thank you I appreciate your help
 

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By not responding, do you mean the control head doesn’t light up over the button you press, or that the compressor continues to run once you select off and the off light illuminates?
 

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Discussion Starter #7
Sorry for the late response, but every button responds normal except for the on and off. Once the fan is on I press the off button and it does not respond but keeps going, It runs for a few minutes and stops then turns on again And so on.
 

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Discussion Starter #8
Sorry for the late response, but every button responds normal except for the on and off. Once the fan is on I press the off button and it does not respond but keeps going, It runs for a few minutes and stops then turns on again And so on
 
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