Glowplug indicator

Iansmithaqua · Apr 25, 2015

Kubota B8200
I have just got a new glow plug indicator, but 3 or 4 years ago I had to replace the ignition switch and left out the second wire on the new ignition switch connections (regretting now). Could anyone explain the purpose of the 2 connections on the ignition switch from the glowplug circuit. I can see that one is the connected to the glowplug supply circuit, what does the other connection serve? The purpose of the indicator is to light when the glowplugs are glowing and the engine is ready to crank.
I will throw in another question; what is the risk of a glowplug breaking on removal from this engine and is the easiest access route with the inlet manifold removed?
Any advice will be gratefully appreciated.
Thanks

kubotasam · Apr 25, 2015

Iansmithaqua said:
Kubota B8200
Could anyone explain the purpose of the 2 connections on the ignition switch from the glowplug circuit. I can see that one is the connected to the glowplug supply circuit, what does the other connection serve?
Any advice will be gratefully appreciated.
Thanks

The 1st wire brings power to one side of the indicator (resistor). After it passes through the indicator the resistance of the glow coil has dropped the voltage to around 9 volts. This first wire is what gets energized when you turn the key to the preheat position.

The second wire (which you left off) brings power from the switch when you put the key in the crank (starter) position. This keeps the glow plugs energized when you are running the starter motor. This second wire connects to the other side of the glow indicator, effectively taking the resistance of the indicator out of the circuit. The current does not need to go through the resistance of the indicator because the large draw of the starter motor drops the voltage down enough that the resistance of the indicator is not needed.

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Glowplug indicator

Iansmithaqua

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kubotasam

Well-known member