Specimen is 1994 E320.

Symptoms:

1. Compressor does not engage
2. Blower Motor works fine
3. Blows extremely hot air when warm

What has been done:

1. Determined there is no power to the compressor at any time
2. Found corrosion underneath battery tray
3. Sprayed WD40 over corroded areas and cleaned
4. Replaced KD/Klima relay unit

Things of potential relevant interest to note:

After I cleaned up the area of the corrosion, and reseated the tray and battery, I started the car and engaged the ACC. I turned on the single-level compressor button (middle) and everything began to function AS IT SHOULD. In other words, ice cold AC, and a perfect compressor function.

Subsequent attempts yielded nothing but the original scenario. What does this sound like, guys?

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1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)

All of the testing should be done at the compressor relay connector.

Are you "good" with a VOT meter? If so I can e-mail you a test plan.

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MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
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44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Thanks, MBDOC. I think I found the problem-child.

This car spent a good part of it's life in a southern climate. I found a broken wire leading to the ACC unit. All wires are brittle, in fact. I spliced into this, and put a new section in. The compressor works now, and air is ice cold.

I think I'm OK for now. But if you have a test plan, I'd definitely appreciate a forwarding for future reference! I'll send you a PM with my email info.

__________________
1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)