Glow Plug Timer Testing???

   / Glow Plug Timer Testing??? #1  

dawii

New member
Joined
Jul 17, 2023
Messages
3
Tractor
sandra55
My glow plug indicator light (and glow plug function) no longer come on when I turn on the ignition. I checked the glow plug relay and that appears to operate fine, and the glow plugs test out fine. I suspect that the glow plug timer (LG4056/LS TRG750 - 4 pin glow timer) may be the problem, but I don't want to spend the money buying parts unless I'm sure it's the timer that's failed - how do you test the timer? No indicator as to which lead is which (three connectors on one row and one on the second row) - Tractor is a DTC300; but I think the circuits are the same on most tractors of that size.
 
   / Glow Plug Timer Testing???
  • Thread Starter
#2  
I traced out the wires from the timer to the relay (a green & a red wire) that are on pin 1 & 3, so I assumed that if I apply 12v to pins 2 & 4, they should energize the other two for 20-30 seconds (thus opening the circuit for the glow plugs). When I tried it, I got 12v to pin 3, but no connection to pin 1 (either voltage or open circuit to any of the pins); and the power never shut off; I would assume that tells me I have a bad timer; but I'm no electronics guy - anyone confirm that this sounds right?
 
   / Glow Plug Timer Testing???
  • Thread Starter
#3  
For any future timer testers :), I ordered a new timer and installed it - and voila, works again.
 

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