Hardwire a 12V to the monovalve. NOT from the battery but from a fuse which is ON when car is running, like the window fuse or others. You only want it to energize when car is running. I went to a junk yard and got the same connector plug, measured the polarity of the plug and wire it to a window fuse. Remove it during winter. I did this for a short while until I realize I had a hairline crack with the fuse.

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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.