HELP! The display on my 95 caddy deville says "low freon". I checked the freon and it's not low. The compressor won't turn on. It just blows out hot air thru the vents. I tried disconnecting the battery to reset pcm and still the compressor won't turn on. I entered the diagnostics by pressing "off " and "warmer" and cleared pcm codes and still compressor won't turn on. When the pcm is cleared should/would it still show history? Please Help! It's very hot here in Texas. Thanks! these are the codes before and after clearing pcm...
p047 history
i022 "
i039 "
i052 "
no acp codes
" sir "
t072 history
t077 "

How do you know its not low?

Blaze

because we hooked it up to the guage to it and it showed full.

When you clear the pcm, the history codes clear off also.

You won't get an accurate measurement of the pressure until you get the compressor running. I refilled a system after a compressor change. The pressure on a good set of gauges, not the gauge that came with the refill kit, showed at least 35psi. The compressor didn't kick on. I went to the pcm and cleared the low refrigerant code. Compressor came on and pressure distributed out through the system. Needless to say, the pressure dropped from 35 to about 15psi. At this point, I had to quickly add more refrigerant before the sensor tripped.

Clear the codes, turn the a/c on max and see if the compressor kicks in. If it does and then kicks off, you will need to top off.

because we hooked it up to the guage to it and it showed full.
The compressor has to be running for the gauges to be accurate. For instance the low side should be between 25-35 PSI, but when the system is off the whole system equalizes and the pressure can rise to over 100. So it could only have a pound and a half of freon and still show way more than full with the gauges while the compressor is off.

Jump the low pressure sensor with a paper clip or jumper wire and then reconnect the battery and see what the pressure is when the compressor is running. If you used the little gauge that is made into the line that you can get at autozone or walmart then the compressor has to be running for sure.

Blaze

You may already know, just let it be stated...do not leave the sensor jumped if you aren't ready to fill up the system. The sensor is there to prevent the compressor from getting damaged. When the compressor kicks on and you see the actual pressure, start filling it to operating pressure. Don't forget to remove the jumper when finished.

tried jumping still no luck. the compressor still won't come on. he is getting power to low pressure sensor but he's not getting any power to the compressor. what could the problem be?

Have you checked the fuse?

Did you jump the connector and while the connector was jumped, disconnect the battery and then wait a minute and rehook it, start it up with the air on and the connector still jumped. That connector would be the thing tripping that Display.

Blaze