John Deere tractor starts with dimmer switch

[hambone11]

My john deere 8520 will engage the starter when you turn the high beam lights on even if the ignition is turned off ,we have stipped almost everything in the cab and behind cab at modules looking for broke, burnt or wires touching cant find anything been at it for almost 2 weeks , dealership said they dont know so here i am.

 

[dodge man]

Is it hurting any thing? If the tractor is running and you turn the high beams does the starter engage.

 

[oldnslo]

Can you access the starter solenoid input wires without dismantling half the tractor? Haven’t been around 8520 for a few years and don’t remember. Would be interested in the wire that engages the solenoid. I would disconnect this wire and then check for voltage when you turn the lights on. If get voltage have to start tracing wires to see where the power is coming from.

Other option would be to use an ohm meter and start checking for common connections between lights and starter.

Faintly recall some wires being to close to exhaust and turbo and insulation getting burnt but don’t recall if that was factory or clamps fatigue and breaking over time.

 

[hambone11]

Thanks for the reply will check in the morning

 

[Tx Jim]

I recommend checking the smaller wire that attaches to top post on starter control relay for bad insulation. If I couldn't locate the problem I route a new wire from neutral start switch to starter solenoid in photo below.

 

[hambone11]

Is it hurting any thing? If the tractor is running and you turn the high beams does the starter engage.

Burnt out a starter

 

[ruffdog]

In the past, I have seen some very strange electrical gremlins and many are caused by bad grounds. BTW...just something to think of.