Has anyone modified a gasser Klima relay for a 87 300SDL - PeachParts Mercedes-Benz Forum

ah-kay · #1 08-31-2009, 03:25 AM

My Klima went south. The circuit is too complicated to repair without a schematic. I just cut all the functions and simply use a relay to monitor the signal from the CCU on pin 10. It works well, I have protection on the freon level but I would like to monitor the compressor rpm as well.

I have access to a number of gas Klima but they do not work on the SDL. It fits in the socket alright but nothing happens. Any idea?

Has anyone managed to modified one for a diesel. I do not care about the other monitoring points but would like to check the compressor's rpm is OK + freon level.

Brian Carlton · #2 08-31-2009, 08:23 AM

If you have the schematics and the skills to convert one of the gas Klima's, you could just as easily repair your diesel Klima. It's nothing but a few relays and circuit board.

I don't know of anybody who'd bothered with it, however.

Jeremy5848 · #3 08-31-2009, 11:45 AM

I've looked at several gasser Klima relays in junkyards; they are definitely different from the diesel variety. Remember that "Klima" is simply a brand name, they build on contract whatever Mercedes wants. We have no idea what a relay labeled "Klima" in any particular car is supposed to do without access to the FSM for that car. It probably has something to do with the climate control system and its interface with the engine but there are no guarantees. Brian is absolutely right -- if you cannot fix your Klima, don't even think about modifying someone else's.

Jeremy

ah-kay · #4 08-31-2009, 01:55 PM

The speed is monitored by a 'LM2903 chip - Low Power Low Offset Voltage Dual Comparator'. I do not have schematic for any Klima, gasser or diesel. I was wondering any electronic whizkid has done any simple change to monitor the compressor rpm. This is to make sure the serpentine belt is not chewed if the compressor is stuck. Let me open up a few Klima and reverse engineer a fix, hopefully.