3840 Glowplugs won't turn off.

[binthere]

I have a Montana 3840 with 65 hours on it no problems until today when I put it in the barn I noticed the glowplug indicator was on. I had been using the tractor about 30 minutes. I turned the key off and on a couple of times even restarted and let the motor run a few minutes. Turned the key off and still the glowplug indicator stayed on. I finaly found a jumper on the alternator side of the motor that felt hot so I pulled it off and the light went off. I would appreciate anyones Ideas.

 

[Jerry/MT]

I don't know anything about your specific tractor but I would look for a relay that puts the power to the glow plugs. It is actuated most likely by a wire from the key switch. It could be sticking shut, which would cause the glow plugs to always be powered.

 

[JDeerekid]

I just had a similar problem with my key switch. It would want to shut the tractor off while I was running it. Then it would not start becuase something in the switch was wrong. I would call your dealer and see if you can get a new switch and go from there.

 

[Inspector7]

I had this problem on a ford pu. The relay shorted out. I would check the relay first.

 

[Sackett2]

Agree with most, the relay is the first place i'd check. the keyed switch provides power constant to the relay, or there may be a timer system also. either way, something is not telling the glowplugs to power down. relay first-easiest and cheapest

 

[MontanaJames]

I have a 4940c with about 220 hours. It is having the same problem. I have been unplugging the relay under the dash and it will go off.

 

[Eagleview]

As stated , it would be the contact points in the relay welded together . But now that the glow plugs have been on for so long they are more than likely burnt out .