jbach36,

Your "Pre Glow Relay" is Electronic (No Strip Fuse) It senses a / an Over Amp,
Over Voltage situation and disconnects
[and then resets when correction occurs]
'Kinda neat (But I don't know the inherent fail rate)
(And I can't find replacements)

My '90 124.128 has one that works fine.
(And I saw one in a '92 124.128 in Texas yesterday)

So to be on the safe side,I'm going to "Fuse" the RED cable [HOT at all times]
[Power to the Pre Glow Relay]with an 80 amp fuse ,just in case.

__________________
'84 300SD sold
124.128