I bought cans of R134 so I wouldn't have to pay $225 for a recharge every time my 1996 DeVille, which has a very slow leak in the freon system, gets low in freon pressure and switches from AUTO to ECON. I am very mechanically able, just so you are aware. I added a small amount of R134 in the low pressure side (per instructions) and raised the suction side pressure. Then I pushed the AUTO/ECON button (car running, of course) expecting it to remain in AUTO. It didn't. Before I add any more R134, I need to know - is there a reset procedure that has to be performed to get the A/C system to be able to resume operation of the freon compressor? Or, should the system remain in AUTO, when selected, whenever the R134 pressure is adequate?

 

Here is a link to a product I used in my GMC. There is a sealer and conditioner and coolant. I post this because you have a slow leak. I finally got the kit after two summers of different shops not being able to find my leak and charging me $459 the last time. This stuff has held all summer and it is cold, I got 19 degrees Celcius at the vents when the outside ambiant temperateure was 31.
http://www.duracool.com/

Have you checked to see that your compressor actually runs? I am sure there is a low pressure sensor at the ac***ulator usually so you can disconnect this and jump wire it to get the compressor going. There is also another low pressure sensor at the compressor usually and the same proceedure can be used. Either one should start the compressor unless there is a problem with the other. Jump the easiest one to reach first. Finally you say you put in a small amount of one can, Are you sure this is enough? I thinkyou checked the pressure with a guage but maybe not enough in the system yet to get the compressor to engage. You need generally 25 to 40 PSI.