Don't know if this is helpful, but I recently had AC problems with my 94 E320 Wagon. Troubleshooting proved difficult because the problem was intermittant. Turned out to be a defective climate control unit. I learned that this part is also sometimes referred to as the compressor relay. Out of curiosity, I opened up the little black box. Inside I found a circuit board containing two small relays, a chip, some resistors, diodes, capacitors, etc..... This unit is more than just a relay, maybe thats why MB calls it a climate control unit.

Part number for the CCU on my car is 003 545 56 05 Don't know if your car has a similar part........

More information on my problem is available in this thread:
1994 e320 ac evap freezing up?

Second to last past details the discovery moment.


J. M. van Swaay

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1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles