Lights Do Not Work Properly on 3020D

When turning light switch on my older 3020D, only the dim headlights work...on all parts of the switch. Dual headlights do not come on. Rear light does not come on and amber fender flasher (added for safety) does not work. I just replaced the starter (24 Volt System), but I wouldn't think that would have anything to do with light malfunctions. Do I need to replace the light switch?

There are two power feeds to the lights on a 24 volt JD light system. One 12 volt positive ground and one 12volt negative ground. These are hooked into the battery system at the starter. So if you did NOT get the small wires back in the correct places on the starter solenoid then the lights will not work right. It sounds like you missed one of the power feed wires on the starter.

Open the panel that the light switch is in. There should be a circuit breakers on the back side of this panel. Take a test light and see if some of them are without power. Then look at the wire colors and trace them back to the starter solenoid. You may have hooked all of them back correctly but one may have came out of an connector or some thing.

To really tell you should be able to see any "extra" wires around the starter you missed hooking up. If nothing jumps out your going to need a wiring diagram and see what goes where.

The JD 24 volt system is not too complicated IF you under stand it is actually two 12 volt systems hooked to a 24 volt starter. So you have to watch loading one of the 12 volt systems and not the other. This is why some of the light feed off of each system.

An example: I had a JD 5020. I wanted a fender mounted radio. I just hooked to one set of batteries giving me 12 volt positive ground power. The radio would slowly drain that one set of batteries. The reason being the voltage regulator saw one side was up to full charge. So it would not charge the low side with out the high side needing it. I wired a light bulb to the positive ground side that would come on when the radio was on. It balanced the lad and the voltage regulator would keep both systems charged.

If I understand it correctly, the generator on the 24 volt system is a 24 volt unit and charges across batteries in series (four - 6 volt or two - 12 volt depending on how it is configured) so even if one or two batteries are low, the overall seen by the voltage regulator and generator would be below the nominal 24 volts and the batteries charge should be maintained.

That maybe how they were supposed to work but mine did not. Truthfully the entire system was a rigged up nightmare. It was way too complicated for the little bit of extra good it would do on paper. In real life it has been proven that a good 12 volt system works better and simpler.

I've also been under the impression that starter technology wasn't quite good enough as yet on the 12 volt versions at the time this 24 volt system was put in place, therefore Deere engineers decided to use a 24 volt starter. I know there is a lot of controversy over the theory of this "split" system.

Ron, you will not find a cluster of 6 Volt batteries on a 3020, that idea passed with the two cylinder er.

I had long figured that if one of the main components of the electrical system needed replacing, that would be the time to switch over to 12V. But the wiring on my 4020 got to scaring me, and the starter and generator were fine (still are!). So, I just rewired it. An update with a little plate and two circuit breakers, mounted on the starter, was included. Now both sides of the system are sourced right from there, with protection. The lack of fusible protection was another thing scaring me. While you're at it, you might want to look into that.

Yes it's possible light switch is at fault. Are the blue & brown wires attached correctly to starter? Is wire attached from LH battery rear post to trans case?

I forgot to click continue to load photo.

Thanks for all of your replies. I would guess I didn't hook up all of the wires correctly when replacing the starter, but with all of your ideas, I should be able to figure out my problem.

Another thing I've seen in the past on non-working fender lights is lack of good light to fender to axle ground(Earth) connection

Bob IRC that JD 5020 had four six volt batteries.