I have my Klima Relay out in the process of cleaning up my cars electrical system and getting rid of all gremlins.

I opened it for fun, since I am always curious and into electronics... I found the relay inside totally fried. Parts of the circuit board too.

I am wondering what can cause this? Bad compressor shorting the circuit? Ideas? For the record the A/C has never worked since I got the car but has charge in it - had it measured.

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99 W210 E220 cdi sedan automatic (248.000 km) 210.006