L2550 glow plug dash unit

[jaydavid]

while badly misdiagnosising another electrical problem as a bad ignition switch and ordering parts, i decided to order a new glow plug dash unit since the old one appeared to be broken. the new one arrived looking just like the old one and upon further examining is nothing but a metal loop visible thru a hole in the cover.

my tractor works fine and actually starts within seconds without use of the glow plug preheat even in the coldest weather. i'm just wonder what is the purpose of the dash unit? my really uneducated guess was that a bulb and cover was missing and the missing bulb somehow pushed down to make contact with the "hot" wire and the sides of the bulb made contact with the cover to provide the "negative" connect. i'm now guessing that the loop is a "heater element" type arrangement and is supposed light up to give an indication of how hot the glow plug is getting, but when i turn my new ignition switch to preheat, nothing happens down in the dark hole.

so what is my new $35 unit supposed to do for me?

 

[birddogger]

The 12V supply for the glow-plugs goes through that little coil of wire first before heading to the glow plugs. The coil glows up slowly, to give you an idea when the plugs are good and hot. If it doesn't glow it could be one of several things; a)no power to the circuit at all. b)broken circuit between that coil and the first glow-plug. c)a burned-out plug, so there isn't enough load to heat the coil.

 

[ipz2222]

That wire will not glow for several seconds, 10 to15, when switch is held to glow position. If it never glows,ie, turns red, there's no current flowing thru it.
If your eng starts without it, don't use it...