KLIMA Basics missing from this forum

[Jeremy5848]

When I bought my '85 300D Turbo, I found a suspicious relay in the box just forward of the KLIMA relay. Eventually, I learned about KLIMA failures and the use of an ice cube relay to bypass the problem and restore a/c operation. I have a replacement KLIMA but would like to know a little more before I plug it in. Although this forum (especially the FYIs) and various books mention KLIMA from time to time, none give a basic explanation of what KLIMA is and what KLIMA does. It reminds me of the FSM -- it assumes you already know.

Therefore, I have assembled what I have been able to glean from the various threads (the books are useless) and present it here for the benefit of other newbies like myself. Perhaps others will chip in with things I have missed.

Anyone have a schematic showing all of the wires to and from KLIMA? I have the FSM on CD-ROM and several other manuals but can't find KLIMA. Perhaps a W124 manual might have it.

What is KLIMA?
KLIMA is an electronic relay system that controls the air conditioning compressor's electric clutch. It allows the compressor to run (engages the clutch). KLIMA looks at many things.
1. It looks at the ACC to see if you want cooled air.
2. It looks to make sure the compressor is not frozen. If the compressor is frozen, the pulley won't turn. The engine would then eat the drive belt and perhaps do other damage.
3. It looks at engine temperature, or maybe coolant temperature, or maybe both. I don't know why. Inputs, anyone?
4. More?

In my '85, KLIMA lives on the driver's side of the engine compartment, just ahead of the fuse box. Earlier 300Ds don't have KLIMA, I'm told. W124 and W126 cars also use KLIMA.

If KLIMA fails, the compressor won't run. Because KLIMA is expensive, people years ago developed a work-around using a small "ice-cube" relay. My car has this work-around. It is recommended on this forum that this not be used as a permanent replacement but no one bothers to say WHY. I assume that it is because all of the safety features are eliminated -- all the relay does is turn on the a/c clutch when the ACC calls for cold air. Right?

Anyone have anything to add?