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Discussion Starter #1
I am trying to diagnose problems with the AC on my '96 S320. It doesn't blow cold and my EC light stays on all the time. I have two codes in the HVAC system:

Ebl 416
Ebl 241

The 416 code is the circulating pump on the duo valve and the 241 code is Refrigerant Fill. From what I read is the EC light will come on when you are low on refrigerant. Having the 241 code seems to confirm that. However, when I hook a gauge up to the fill port, it shows around 47 PSI - which is around where it should be.

Any ideas what the issue might be? Bad sensor somewhere?
 

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Doing that with the engine off only tells you that there is some R134a in the system, but not how much. If it's not being compressed, the gauge only tells you what the vapor pressure is. Try temporarily jumping the pressure switch and see if the compressor kicks in. If it does, check the sight glass on the receiver/dryer. If there are bubbles, add 134a until they disappear. If it is really hot outside, you may still get a few. After adding one can, try reconnecting the pressure switch. If it still doesn't come on, the switch is bad, and the system will have to have the refrigerant recovered to change it. Then you need to pull a vacuum for at least 30 minutes, and recharge with the correct amount of 134a by weight.

The best way to recharge in any event is to recover refrigerant, pull a vacuum, and add the proper amount of 134a by weight. The sight glass is an approximation at best.

A good set of gauges doesn't cost all that much, and reading both the high and low sides will tell you far more than the crappy low side gauges on refill bottles.
 

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Discussion Starter #3
I was running the engine when I took the pressure reading but as noted, the compressor was not running.

I'm struggling trying to figure out which sensor is the pressure switch. I have access to alldatadiy but in there it shows two sensors on the receiver/dryer. One is a two-pin sensor while the other is three-pin. I have attached the screen shot. I tried jumpering the two-pin connector but the compressor still doesn't run. I don't know which pins to try to jumper on the three-pin connector.

On a side note, I have noticed that when I have the climate control on, key on, engine not running, I hear the PSE pump cycling. It doesn't do that if I turn climate control off. A couple of weeks ago I had the PSE pump out as my central locking system was not working. I found in the pump that the red hose had popped off. Putting it back on and securing it with a zip tie seemed to solve that problem. My AC was not working even prior to that.

Does any of this fit together?
 

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Discussion Starter #4
I figured it out. Further reading I found that if the EC light is on and won't turn off, you must reset the diagnostic codes before it will turn off. With it on, you won't be able to get the compressor to run. Resetting the codes allowed the compressor to run and let me charge the system. It is now blowing cold air. I put UV dye in the system so I can locate any leaks.

I still hear the PSE pump cycling periodically when I have the engine off and the climate control system on. I'll have to chase that down as I suspect I may have a vacuum leak.
 

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Discussion Starter #5
The cycling PSE pump was due to a leaky bladder in the passenger side lumbar adjuster. Set it to zero and the PSE pump no longer cycles.
 
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