Glow plug wiring

[Steve777]

I recently replaced the ignition switch on my S470D with an OEM switch. Easy just moved the wires over from the old switch to the new one. However I am now wondering if perhaps the wires for the glow plugs might have been wrong on my tractor.

The glow plug heater on the dash never glows or gets hot when I have the switch turned to run the GPs. However the GPs appear to work. When I was replacing the switch I noticed that there were two wires from that dash heater, one on each side of the coil. On my tractor they went to two posts (G2 and G3 from memory) on the switch. I was wondering if that was right???

I'd assume that heater coil was supposed to be in series with the GP's, to reduce the voltage to them. If that were the case, then wouldn't only one side of the heater coil go to the switch, and the other go to the GP's?

Anyone out there know how the GP's and the dash heater coil are supposed to be wired?

TIA

 

[Ilikeurtractor]

Read here:

http://www.tractorbynet.com/forums/mitsubishi-satoh/268403-mt372-wiring-diagram.html

and here:

http://www.tractorbynet.com/forums/mitsubishi-satoh/262931-mitsubishi-s373d-2.html

 

[Steve777]

Thanks.

From the looks of that wiring diagram, seems that there should be only one wire to the switch from the heat coil and then the GPs run off the other end of that coil. That's what I would have expected if they were using low voltage GPs. But that was not how my tractor was wired. I'll need to do some investigating to see which ignition switch is the GP position (my switch numbering is different than the diagram), and change it back.

 

[Ilikeurtractor]

I think the bottom line is you'll want the power going through the indicator (coil) in the "heat" position and by-passing the indicator in the "start" position. You can probably get away with not powering the plugs in the "start" position but ideally that's how they should be.