Massey 1230 Glow Plug Indicator - Missing

[falgra]

I simply wanted a picture of the facotry style so that I can look for a factory matched replacement. Mean while I am going to simply short the connectors together, as having to push the button as well as hold the switch is quite a PITA. Thanks for the picture and the help, now I have somewhere to begin from! I called Agco again, and they still keep telling me the 1230's do not have glow plug indicators. your picture proves otherwise and confirms what I thought.

 

[falgra]

Found the part. 3704243M1 for anyome else looking for it. 43$ from jacks... ouch...

 

[falgra]

Found an isuzu part on ebay for $20 shipped that cross references. Isuzu: 5-81420041-0

 

[PILOON]

I hear you guys state that the indicator light is in series with but I believe that actually it is parallel to the glow plugs which in turn are parallel to each other.
If they were is series then any one failure would annul all.
Also if indicator was series connected its failure would deny power to the plugs which is not the case.
The indicator is merely a wire resistor that glows at the same rate as the plugs getting redder as it gets hotter.
It will be a short length of coiled nichrome wire of the proper resistance.

 

[falgra]

While that may be true. In my situation it is most certainly in series as unless i press the normally open switch 0v goes to the plugs.the harnes positive wire from the glowplug side of the ignition switch hits one side of thr button, which passes the positive voltage through the swit h and then to the harness leading to the fusebox. From there it goes to the glow plugs which are also wired in series from one another. Maybe Massey didnt get the memo on mine? Wiring looks factory.

 

[Porschemann]

Somebody has a done a rewire on your tractor. Normally turning the key counterclockwise will pre glow the plugs, which ARE all wired in series, along with the glow indicator. If any one in the circuit goes open, the glow plug circuit does not work.

 

[PILOON]

While that may be true. In my situation it is most certainly in series as unless i press the normally open switch 0v goes to the plugs.the harnes positive wire from the glowplug side of the ignition switch hits one side of thr button, which passes the positive voltage through the swit h and then to the harness leading to the fusebox. From there it goes to the glow plugs which are also wired in series from one another. Maybe Massey didnt get the memo on mine? Wiring looks factory.

"Wired in series from one another" LOL, that is wired in parallel!
Series is like with a battery,series= + pos to neg and and parallel = + to + and - to - !
On the glow plugs the engine is ground and the terminal is pos and since all the terminals are wired together they are in PARALLEL.
Confusing I know and don't feel bad as that is very common misunderstanding.

In parallel the failure of one still allows power to the others (engine would start but sputter, skip until warmed up)
In series nothing would happen as there would be no ground path to complete the circuit.

If you take battery + with a jumper to any plug you will have all the plugs heating up. (max 15 seconds) and you should start up.

 

[PILOON]

A caution here,
If using another brand indicator you would need to be sure they have same values (resistance) as otherwise the indicator might not glow at the same rate as the plugs.
Your plugs could in fact be burned out and the indicator not show the slightest glow yet.
Fact is many if not even all depend on a timer to control the heating cycle in which case an indicator is not even needed.

On my tractor I needed to replace the switch and the indicator never got connected but the plugs still work OK.
I can actually hear a 'clack' sound when the timer relay cuts out and know that I am good to go.
When it is real cold I sometimes cycle twice.