Air conditioning compressor on 95 deville is intermittent. New compressor installed, correct amount of freon, blows cold sometimes othertimes compressor will not come on

did you use the correct type of Freon for the compressor type?

check for compressor clutch operation, if the clutch is engageing you could have a bad compressor or a blockage in expansion valve

In this case you may have one of two things going wrong, Either there isn't enough freon in your a/c unit or you have a bad switch

Sometimes yes, you will need to jump the cycling switch or also called the low cut off switch, this is located on the filter dryer,a quick note, if the system has air or moisture in it and you charge it you may get cold air to blow but will cause damage to the compressor over time and cause it to go bad. the correct way is the evacuate the system and then vacuum it down and then fill with some oil and fill with the correct amount of freon,without gauges its hard to know if you are adding the correct amount and this causes damage over time, just because its blowing cold doesnt mean it fine, good day, hope this helps.

If the freon is at the correct level and your AC compressor is teh most likely candidate. Have the AC compressor checked.

This is most likely the cycling of the AC unit. As the compressor pressurizes the 134a Freon you get the cold air, once it reaches a certain pressure it cuts out. If you are low on Freon it will cycle out more often. Check your freon level with a gauge to see if your within the proper tolerance. If the compressor runs for a period and doesn't reach the right pressure it will cut out to keep from damaging your compressor so it is important to keep the correct amount of freon in the system.

I can tell you general principles about A/C but have not worked on a Hyundai. If the A/C lines under the hood and directly from the black cylinder tank are frosted or sweating, you have Freon circulating.

There are 2 cutoff switches in all systems. A low pressure and high pressure cutoff. The ideal amount of Freon is in the middle of these 2 pressure points.
In this way the compressor clutch will stay engaged the longest and keep the Freon circulating the longest. This is the way you get COLD air.

There are ways to measure the pressure and to find leaks. You can sometimes loan tools from Autozone or Oreillys for a deposit. Before blaming another electrical problem for the lack of COLD air you should test the pressure of the Freon left in the system. If you are within 90 days or 3000 miles, most minimum warranties cover the parts. With factory warranty it should go farther.

In answer to your electrical concern, yes there is another system controlling the A/C. The ductwork has either vacuum operated or electrically operated doors (flaps) under the dash. These "doors" blend the airflow by mixing cold and hot air to give you the temperature you want. If you want all COLD you keep the heater door shut and so on.

So you look at these areas separately first. Under the hood is the Freon pressure good? Pipes sweating? Compressor clutch on steady? And if everything under the hood is good, then you look inside the car at the ductwork.

I hope this helps you.

Does it have the correct amount of freon, it can still blow cold with the wrong amout of freon, this will damage the compressor,you may also have a bad cycling switch or bad high preasure switch and even a bad connection to ac system,this first thing is to make sure the correct amount was installed,

on my 99 devillle concours cold air blows from left and back vents but hot air blows from right vents

Hi,check if the compressor clutch is engaging,if not check the conection at the compressor if ok check,fuse ,or relay ,if those are fine and the commpressor is engaging,check freon presure ,may be too high or low, if this is the case ,correct the problem and disconect the negative cable from the battery for a minute to reprogram the sistem..C1