AS per the diagram for 1982 300SD that I have:
REPLACE F10 and F11 in fuse box (humor me on this vs. "checking" them).
Jumper wires at plug to ETR. Make sure you're at the ETR on the driver's side by the accelerator pedal (inboard of it). The link I gave you is it. Should be BK/RD and BK/RD/GN wires.
Jumper the wires to the low pressure switch (black "pot" with two male spade connectors) on the R/D. Jumper the wires
. Should be BU on one side and two wires together on the other BU/GN and BU/GN/RD. I know you know, but it never hurts to say it again.
See if it works. Check voltage at the wire at the compressor plug BU/GN and BR (ground is brown on MB's).
If still not there, swap relays (they're just the same old ice cube relays; no fancy-schmancy Klimas on ours
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