I have an 97 850 GLT with A/C demons. The fact that sometime the A/C blows cold for hours and other time 30 secs may make me think that the freon needs re-charging. Except the times it blos for seconds and quits is when it's between 75 - 88 degrees outside. If it's above 90 it blows longer then quits. Above 100 it usually works pretty good. The strange part is that the driver side blows cold and the pass side blows luke warm air. I pulled the sensor on the pass side and it seems clear and when I unplug it, the A/C unit lite blinks for 20 seconds, making me think it is working in the first place. And the Air still doesn't blow colder with it unpluged (pass side). I guess I could pay the $175 to have the system re-charged and see if it fixes the problem, but with the two sides blowing differnt temps, I think there is something else wrong and it would probably be a waste of money. Especially since at 100 degrees it will blow cold for hours of driving sometimes and only minutes others; doesn't seem like just being low on freon would do that. Anyone had any similar experiences or input?

Kevin

 

Welcome to the forum.

If you do a research, you would find a countless number of threads related to the A/C. The A/C in 850 is noted for failure due to one or more of the following reasons:

- Evaporator that is guaranteed to fail.
- Faulty compressor pressure switch that shuts off the compressor & keeps the system cycling.
- Compressor shim being out-of-spec. Moderator Tech has a pinned post on this on the 1st page of the 850 forum.
- Damper motor(s) that is seized and needs to be re-calibrated or replaced.

Yes merely recharging the system with R134a is a waste of money and it probably won't fix the problem. The blinking LEDs can sometimes be ignored, as long as the system functions after the blinking stops. For '96-'97 models, you would have to visit a dealer to have the system reset or have it diagnosed, whereas '93-'95 can be diagnosed without any tool or tester.


JPN

 

Actually I wouldn't punt on the evaporator just yet.

Chances are that you have a slow leak somewhere as your symptoms are those of a low charge of R-134A but they don't sound - yet - terminal.

As the temperature increases the pressure on the system also increases. From ancient history in engineering school thermodynamics class PV=NRT.

As the temperature increases the system pressure increases which causes your low pressure cutout switch to not cut out. I'd dump a can of R-134A in the system and see what happens.

If you really want to know what is going on with the system you will need to buy a gauge set.

...Lee

 

I would start looking at the compressor gap first before freon level.