1992 Cadillac Seville V8 Front Wheel Drive Automatic 225000 miles
The clutch on the A/C cpmpressor of my 1992 Cadillac Sevelle won't engage when I try to run the A/C. The " Auto" light remains lit on the dasboard display in the climate contrl section shows. The code on the diagnostic display shows a code 'A12' as 'current'. Although I tried to clear the code, it will not clear. I'm unsure if this code means that the refregerant is low and this is a pressure reading of the low pressure side. However, my ohm meter shows that the low pressure switch should be good as I get a continuaty reading when I test at the switch side with the sense wires unpluged. If I jumper the the sense wires at the connecter, it still won't clear. Also, when I test the ground wire to ground, it reads continuity. When I test for power on the power side of the connertor wire I also do read 12 volts! What am I misssing?
A012 is the low side temp sensor circuit fault. These are the small sensors on the upper high side line-both sides of the orifice tube low side temp being closest to evaporator. I believe these are 5 volt sensors, you might be on the pressure sensor. It sounds like you may know how to access the on-boards, if you can access ACP data, parameter AD28 is low side temp. Check it's reading, if it is high(94 to 102), disconnect and see if it registers -40. If it does, replace the sensor. These sensors fail, sometimes the orifice tube is installed backwards and it shears off the thermistor, and there could also be connection faults with the micro terminals. GM offers a replacement connector with leads that attaches in place of existing connector with butt connectors(or solder is an option). When you remove these sensors, the system needs to be discharged. You can try swapping one sensor with the other and see if your code changes. A011 would be the code for hi side.