Glow Plug Indicator Light Slow Going Off

[Keuka]

I own a 2001 Kubota L35 TLB. Lately I've noticed that the glow plug indicator light stays on much longer than it used to, maybe 3 to 5 minutes in warm weather (75 degrees). It never used to do this so I'm thinking either the glow plug or most likely some type of thermostat indicator is beginning to malfunction or the contacts need cleaning. I'm wondering if this might be a common problem and hopefully a simple fix if I knew where to look first? If anyone might have had this problem and might offer suggestions on where to start my search it would be appreciated.

The machine starts right up even when the light is on but I'm hesitant to let it run, with the light on, for fear of maybe scoring a cylinder or something. I'm thinking it's probably a sensing or sending unit because as stated, the machine starts right up and it's not cold out, yet. In addition, if I shut the engine off "sometimes" for say 15 to 20 minutes after use and the engine is obviously still warm, the light comes on like I'm into a cold start situation. Would I be safe to let it idle and warm up with the light still on, I'm not thinking of just using it under load, just idle to warm it up and speed up the light going off before using it under load? I really would much prefer to find and fix the problem but just wondering about idling unit the light goes out.

 

[RustyA]

You could do a resistance test on each glow plug. If they ohm out within spec it's likely the controller or relay is getting weak?

 

[jaxs]

Many (maybe all) properly working glow plugs remain on after light go's out but 5 minutes sound's excesively long. As Rusty said,ohm plugs and go from there.

 

[Roadworthy]

You could measure the voltage at the glow plugs to see if they are actually receiving power while the light is on or if just the indicator is affected.