OK baffling Glow plug issue 1984 300SD

[meltedpanda]

So my glow plug light has been out a few days.
So I
tested idiot light - good

tested relay , volts to it - good, timer relay on 20 seconds, 12+ volts to each pin

tested from plug to each glow plug, all ohmed out below 1

when plug is diconnected from relay , light on dash glows

reconnect it , does not come on

what am I missing, too much time under the SL hood has me stupid

seems that if the plugs are good, relay working --what is left???