I have been reading, and reading on this forum but am more confused. I have a 93' 500SEL (143K miles) Last year AC was fine. This year nothing. My reliable Indy said the compressor was locked up. I had them replace the compressor and drier. It blew cold for 3 weeks. I did not use it for a week, and now it blows hot. It didn't even get progressively hot. I don't think my compressor comes on, nor do the aux. fans. There seems to be some greasy liquid on the new drier. (Possible leak?) I am taking it back in for a pressure test. My question is, is there other things I can have them check, just in case they are clueless on the switches and sensors on this car. This car is rare in these parts, and I am loosing confidence in them. I know of the Evap. woes. If the pressure is OK now what? If it isn't then what? Diagnostics on the controller were:
1. 23
2. 94
3. 87
4. 87
5. 88
6. 14
7. 3
8. 10
9. 30
Can someone check these out and interpret?

This forum is awesome.
Thanks

on that model i would wonder if the a/c evaporator was leaking. usually when you see an excess amount of codes as yours has, the a/c control panel may be defective, or the wrong one may be installed.

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I have a '92 300SE, and would assume the codes would be very similar since the cars are only 1 year apart.

23 & 94 - show no such code values (as such, the rest may be suspect as well)
87 - intermittent fault with the duovalve unit
88 - A/C Compressor Ground Activation - didn't get much info here. AllData says to test some pins on the left-hand climate control unit connector (inside dash) - should be 9-12v with control set to EC, and <1v with control set to defrost.
14 / 3 - point to problems with the rear A/C control module. (If your car doesn't have rear A/C - as identified by temp-control wheels with an additional fan-speed control in the rear compartment), the I'd ignore all the rest of this.
10 - repeat DTC readout ????
30 - Right heater core temp sensor - open or short circuit (continuous fault)

Don't know if this is much help. You definitely shouldn't see any oily substance on the dryer area - I'd take it back to the folks that did the work.

The A/C pushbutton sends a signal to the BASE module...that base module turns the compressor on.

If the compressor never comes on, possibly that base module has a code to BLOCK the a/c operation.

A good MB scanner can read codes & LOOK at "live" data to see if the command from the pushbutton control is ACTIVE.

Have you disconnected the wiring at the compressor & yank on those wires? they do break there.

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I would put money on the evap....

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