1998 cadillac deville reads service ac system

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

Either connection is bad to low pressure sensor or pressure sensor is faulty.

on those caddys you disconnect the battery and wait a few seconds and reconnect and it will reset ac system. when it goes into service mode the system just shuts down. the battery procedure is how to reset. when the ac compressor is not engaging you will not get an accurate reading on your gauges. it might be low but the compressor must be engaged for the system to take more freon.

OK, if the A/C system has been discharged of R134a for any length of time, the car may have to be reset by disconnecting the battery and reconnecting after a few minutes.

That's the way my 1990 Cadillac Deville is, as it's a safety measure for preventing low freon level operation of the compressor which can damage the compressor.

My 1997 Cadillac Deville Limo hasn't had any leakage issues, so I don't know if this would work on that late of a Cadillac.

After adding r134a to the low side, and if the compressor doesn't work, then this could very well be your problem.

Good luck on this repair.

I would try charging the ac system with some freon,and see if that is the problem,the ac compressor will not come on unless the ac has freon,and enough to turn it on,disconnect the negative battery terminal for 25 seconds before doing this to reset the ac system.

You probably have leaked out your freon after so much time. Try adding some more Freon if it doesnt stay charged you may have bigger issues.

You can buy a can or,refil kit of R-134-A at walmart however only put the freon in on the low side (read the directions) if the freon gas will not go in; run an 18 gauge wire from the battery to the compressor clutch switch to run the compressor if the freon gas still won't go in it must be evacuated and, recharged by a shop. only put in enough freon to get the system cold any more than that and, you will lose cooling again (over charge)

Locate the Low Presure Switch on The COLD Line And Jump It With a Paper clip See if this Ingages Compressor KEY ON

Check the wire connectors and wires for any breaks that are on the A/C line.