Auto Air Conditioning & Heater Repair: auto a/c, 1997 buick skylark, skylark 3

Question
QUESTION: 1997 buick skylark 3.1...   a/c  is fully charged  new serpentine belt the clutch engages when i apply 12v to it with seperate wire ....but when car is running it won't  engage .....  any ideas  where to go to?  fuses are good heater blower and system works....

ANSWER: HI Jose

You need to see what is missing at the clutch.  Is it ground or positive signal.  Let me know and I'll try and help.

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QUESTION: 12 volts missing @ the clutch.......i don't have a wire schematic for the a/c system .........  the system engages when i apply  12 volts to it directly from the battery........cannot  find where i;m missing the signal from

ANSWER: Check your cycling switch located at the accumulator or on the suction line.  You should have power going in and out of it.  You can put the two lines and see if compressor starts. If that does not work then check you relay make sure you have power and ground to it.  With relay off you should have two powers and two grounds.  If you do connect relay and listen for a click.  If you have the click and no compressor your relay may be bad.  But I'm almost positive your cycling switch is the problem.

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QUESTION: there is no power to the switch..........

Answer
Ok lets start all over.  First check fuse if both fuses OK then.  Check relay you should have at least one positive without ignition on and when (ON) you should have two positives.  If so then make sure you have two negatives. Again one with ignition off and both with ignition on.  If you do then the negative that stays on with ignition off run a positive to it and make sure your compressor engages if it does then your relay is bad.  If it does not then check for an open in that wire going to the compressor.   NOW if you have both positives and both negatives at the relay and your compressor does not engage.  Check the connector at the compressor and make sure you have 12 volts on one side and a negative on the other.  Don't worry after you do all that if you can't find the problem let me know and give as much info as possible.