Ford 1900 glow plug indicator

[Jafo20]

Hello All .... my glow plug indicator melted immediately when I turned the key to the left to warm the plugs. Can anyone tell me why this happened? I did purchase a new indicator coil but I知 afraid it will melt the new one.
Thanks

 

[JC-jetro]

If your flow plug indicator is small coil of wire then it is in series with glow plug circuit. It is just like a resistance heater. It sized and calibrated to glow red in a several second so you would have a visual indication of adequate glow plug time. They can get oxidized when they turn on and of cycles. The only time it melts right away is if it is grounded somehow. just used a small piece of copper wire, low gauge purpose 16 or 18 and install it where indicator wire is, put the voltmeter on the glow plug wire lead and see if you can get 12 volt at the glow plug. if your short piece of wire melts again then you have a short. Find the short before you put a new glow indicator wire on. Your short piece of low gauge wire is pretty much acts like a fuse.

 

[Jafo20]

Thanks.... I’ll check it out. Where would I look for a short? Or ground? Thanks

 

[JC-jetro]

Thanks.... I’ll check it out. Where would I look for a short? Or ground? Thanks

it is difficult in one sentence too cover all potential areas that wire will have a short to the ground. when you turn the switch to preheat the wire from switch to the one side of the element should show 12 volt (basically connect a positive end of the meter to that wire and negative to the ground near by on sheet metal/chassis somewhere that is not covered with paint. if element not melted you should read 12 volts upstream right were the glow plug wire connect to the glow plug. look at the wire that connects to the glow plug to see if it is damaged and touching the engine block. Again if you jump with a short piece of wire where the glow plug contact are you can still pre-heat the plug but you shod be the timer. For me , I don't even look at the glow element and just count to 10 seconds and it is usually is adequate. I can see the wire is trying to get red. Now if the engine is very cold in the iddle of the winter then I might count to 15 and then element is bright red. You probably need to remove fuel tank to have room to get to glow indicator. If you can don't remove the fuel line since then you will have to bleed the air and purge the fuel pump which you don't want to do if you have a choice. you can bleed the air from fuel bowl before it goes to the pump.

I would jump the glow indicator to see if I can start the tractor before anything else.