# John Deere 4040 Dies When Using Headlights



## paoutdoorsman (Apr 23, 2016)

Need some help figuring out what is going on with this 4040. Starting to use the headlights now with the shorter days. Two nights in a row last week I flipped the headlight switch to the last position which provides the fullest lighting, and immediately the tractor died. It's almost like a circuit breaker flips and there is no dash lights, no power, and no attempt to restart. Patience wins; walk away and come back 30-60 minutes later, it starts up and runs fine like nothing ever happened. I was living with the problem by just having less light, but tonight after mowing with it for 30 minutes with only the road lights, I downshifted at the end of a round, and it died again. This time it started after I made a 10 minute phone call and was fine the rest of the night.

It is the Euro model so it has an electric fuel shutoff solenoid on the pump that shuts the tractor off with the key, rather than a pull cable fuel shutoff, which is why I believe it dies when it loses electrical capacity.

Is there a self resetting circuit breaker somewhere on this tractor? Or any other ideas?


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## somedevildawg (Jun 20, 2011)

It sure sounds like there is, and/or there is a short circuit in the light circuit, I would probably check at the switch first......of course, high beam headlights are purty much a direct short anyway, maybe a bad connection at the switch that's causing resistance in addition to the headlights.....
I also had a WOT set screw back out once and short circuit the main fuse (30 amp) in the fuse box, the cold start relay wire (I think) runs behind the set screw.....it would only do it occasionally so I put a circuit breaker In place of the fuse until I could find the problem, which I eventually did......


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## Wethay (Jul 17, 2015)

Good excuse to go to LEDs. I second the thought of checking at the light switch. Does that have fuses or circuit breakers?


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## Tx Jim (Jun 30, 2014)

I have very little experience with the 40 series rowcrop tractors built for European sales but 1st thing I'd recommend is checking snugness of all connections on the circuit board in photo. These connections have a long history of getting a little loose causing heat which will trip the circuit breakers. Circuit breaker board is located in frt of dash on LH side accessed by removing cowing between dash & hood. One would need to view for European 4040 tech manual for wiring schematic.


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## paoutdoorsman (Apr 23, 2016)

I did put a new OEM Deere headlight switch in the tractor this spring. The old one had lost the detente clicks for each position, and I originally thought that was the cause of this problem.

I'll have to pull the cowling and check if one of those circuit breakers is guilty the next time it happens. Do those things tend to weaken over time?

Buying a service manual, and upgrading to LED's are both good ideas, but I think I'll be parting ways with this 4040 before too long.


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## Wethay (Jul 17, 2015)

I can't remember how this specific model of tractor is set up, but on other 'Deeres the circuit breakers were on a brass bus bar. Over time the connections get loose or corroded, causing resistance. Resistance equals heat and circuit breakers trip because of heat.


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## paoutdoorsman (Apr 23, 2016)

That matches up with the image that Tx Jim posted up above. I'll have look at those bus bars once I remove the cowling and maybe just clean them up good to see if that helps. It's interesting to me that the headlights wouldn't be on their own circuit and have their own circuit breaker. It's like there is a main breaker that trips and kills everything.


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## Tx Jim (Jun 30, 2014)

paoutdoorsman said:


> It's like there is a main breaker that trips and kills everything.


I can't remember if the accessories relay(key 27) supplies headlamp circuit or not.


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