The compressor starter is faulty. It fails to start the compressor. It is used only to kick start the compressor then it is not used anymore. You can replace it if you know the part number. Most HVAC company stock them.

You can see whether you can remove it, clean the connectors and shove it back in. It may work again but it is on its way out. It is attached to the compressor where the wires are.

Have fun.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.