'95 S320 A/C problem
 

I just replaced the compressor (a re-man), dryer and expansion valve on my '95 S320. We thoroughly vacuumed the system after cleaning with the proper solvent, recharged to just a bit less than 2.5 pounds of R134.
The problem is that the compressor turns on for about 10 seconds and then off for 2-3 minutes, the starts over for 10 seconds, off 2-3 minutes, etc. All the pressures are within the specified range. The compressor runs good when we hot-wire it directly (although it does not cool more than a 15 degree drop). I replaced the pressure sensor on the dryer and now have no diagnostic errors coming up. The belt tension seems OK, I sprayed some cleaner on the clutch, just in case. Any ideas?

maybe the evap temp sensor? It is getting too cold and the system shuts the compressor off to reduce possibility of freezing, what about the expansion valve? Just some thoughts.
B

Thanks, I'll take a look at them. Any idea where the evap tem sensor is?

Another thing that would be an easy check, some compressors have a speed sensor on the rear of them, this is to ensure that there is no drive loss due to clutch or belt slippage, if that speed sensor is malfunctioning or not connected properly it will let the compressor run a bit and when it senses the engine speed is not consistent with the compressor speed it will shut it down. Just another item to check, if it is a Nippo compressor it likely has one.
Brian

If you send me your email address bwheitman@comcast.net I will send you the testing and diagnostic procedure for that climate control system.
Brian

I sprayed some cleaner on the clutch, just in case. Any ideas?
<<<

Depending on the cleaner , you may now have a slipping clutch..which willshows up the same as a slipping belt.

Thanks, yes it was a zero-residue cleaner. After looking over your diagnostic chart and some of the other posts, I ordered a new evaporator temp sensor. The reading on mine was very high. I'll update in a couple of days if this fixes the problem. Thanks again for all the advice :)

Diagnostic E0 00 ?
 

DOes anyone know what a E0 00 is on the A/C diagnostic? It's not on the list I have.

All stored codes have been cleared/deleted...

Thanks, Arthur. The new evap temp sensor did not fix my problem, either, I'm quickly running out of things to try.

Now that you know all codes are claeared, Run it agan a few times and go back and see what faults are being detected..

Aux Fan issue?
 

With the replaced sensors, I now get no faults or errors, and the same intermittent running of the compressor. But, an odd thing is occurring (or I just now noticed it). When I punch the right "Auto" button while in diagnostic mode, the auxillary fan kicks on for a few seconds every time I press it. I then unplugged and jumpered the pressure sensor leads, as was suggested in the archives, and the auxillary fan does nothing. The pressure switch is new. The only way to activate the low speed fan is to ground the center pressure lead. Unplugging the temp sensor on the thermostat housing activates the hi speed aux fan as it should. It almost seems as if its a grounding problem but, with no error codes it is difficult to know where to start?

Errors or faults: none

Actual Sensor values:
1 - 97 deg in car temp sensor
2 - 95 deg outside temp sensor
3 - 100 deg left heater core temp sensor
4 - 100 deg right heater core temp sensor
5 - 98 deg evaporator temp sensor
6 - 103 deg ECT sensor
7 - 8 refrigerant pressure in bar
8 - 45 blower control voltage
9 - 30 software status
16 - 0 active charcoal filter "no"

Wow, that has become a challenging problem. Do you think the ground is bad to the pressure switch? Did you test to ensure the pressure switch is closed? Try taking the lead that activates the fans when grounded, put it on the switch, take a fresh ground lead and hook it to the other side of the switch. That will tell you if the existing ground to the switch is bad, so when you activate your fans, does the compressor run ok? If so then the it is likely shutting down due to freon temp? I don't know if that is the problem, but could be. I would also think that if your compressor speed sensor was malfunctioning it would cause a code. Hmmm, maybe it is the controller? The push button deal in the dash, you said you replaced your compressor with a reman one? I know you don't want to hear this, but if it was all working ok prior to replacement, maybe the compressor is bad. Just some ideas.... I have never had a problem where a code didn't show up to tell me what to fix (except on older cars where no computer was installed) so really with no codes it is a hit a miss.
Brian

<<I then unplugged and jumpered the pressure sensor leads, as was suggested in the archives, and the auxillary fan does nothing. The pressure switch is new. The only way to activate the low speed fan is to ground the center pressure lead. >>

I do not know which archieves post you refer to, but the pressure sw [ high side pressure] jumping suggestion in the archieves
is probably from a 124 chassis type set up [ 2 wire pigtail].
You have a 3 wire combined sensor and this test does not apply to your set-up. I believe center ground is the test for 3 wires pressure sensor for fan circuit.. I will check schematic on that for verification when I find it....