If you are not getting anything at the valve, the test is to remove the control unit and bridge pin 1 to pin 2 and pin 4 to pin 5 simultaneously for a short time. If the valve clicks, then replace the control unit.

You could also do a Search and find my recent post on how to make a restrictor that will slow your idle down for cheap.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe