Hi, my 1991 300E "hisses" when I have the climate control set to A/C (I don't think it does it on EC). It sounds like a sucking straw sound about every minute or so. It's not very loud, but is noticeable. I recall my 1985 380SE used to do this too. Is this normal? Has anyone else out there experienced this?

The climate control and A/C works great for the most part. It did shut off on me 1 time in the last 6 weeks - actually, it didn't shut off but it switched the fan to the lowest setting and turned off the compressor briefly, then took about a minute and a half to slowly build back up to normal A/C operation with medium fan and compressor cycling on and off. I'm interpreting this to mean that the pushbutton unit may need to be resoldered soon - can anyone verify this?

As for the hissing - is this normal?

Thanks in advance!

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