|
Greg, I can't speak to your particular application, but most all of those old heating systems used 12v glow plugs. And basically, the glow plug was just routed directly to the 12v battery voltage via that manual hold down switch. The gauge circuit was then run in parallel with the plugs to show the operator that the circuit was complete when the button was being held down. The nice part about this old system was that it was almost impossible to "hurt" the glow plugs by holding them on too long. They just kept on heating. Newer systems use a 6v plug which is turned on and off by a solenoid and the 12v feed is then routed thru a 'controller' to the plug. This gives a very fast 'heat-up' time at the plug, but just like a 6v light bulb, the voltage has to be cycled or else that plug will burn itself out since it is being fed 12 volts. In other words, the 6v plugs have to be "pulsed" on and off by that controller. The upshot of this is that if you see a system with all of the glow plugs burned out, the first place to look is to see if someone somewhere has installed the wrong 6v plugs. Very easy to do because a lot of aftermarket partsmen don't catch the difference in a glow plugs' voltage. Now, neither system uses a resistor in the main wiring to the plug that I am aware of. However, there may be a resistor just in that gauge circuit to keep it from being a direct short to ground. But, this would only be in the gauge portion of the circuit. The voltage requirement is stamped on the plug just under the spade or the nut. If yours say 6v and your tractor has a 12v electrical system with a manual "push button" glow plug system, I think your tractor has the wrong glow plugs installed. Hope this helps, Allan
| 
