The aftermarket light switches for a John Deere 720 and 730 diesel 24 volt electric start (2 head lights) and a John Deere 70 conversion with two head lights are very expensive. I assume that is because of the resisters on the switch which feed the head lights. Tractors with four head lights have a cheaper switch. Are there alternatives, substitutions, or updates to the $130 plus switches? The switches for 24 volt - 4 head light tractors are about half price to the 2 head light switches. Would consider a good used switch as well. Last question - on the back of a 24 volt - 2 head light switch the terminal marked GEN is raised short of a 1/4 inch from the plastic backing with a bushing. What is the purpose of this? The bushing doesn't seem to conduct electricity. Sort of a technical question. Thanks.
- Thread starter andy r
- Start date
Are you sure they are resistors? The diagrams on page 80-5-20 of Service Manual 2029 Electrical Systems don't show any resistors. There shouldn't be any resistors in the light circuits, unless they are being supplied from 24 volts. I haven't worked on those lights so I may be all wrong.
" Are you sure they are resistors? The diagrams on page 80-5-20 of Service Manual 2029 Electrical Systems don't show any resistors. There shouldn't be any resistors in the light circuits, unless they are being supplied from 24 volts. I haven't worked on those lights so I may be all wrong."
Yes, they are resistors, used for the "DIM" headlight switch position.
The device at the "GEN" terminal is a resistor, as well, approximately 50 Ohms. It's purpose is to allow the use of a standard 12 Volt indicator lamp on the 24 Volt charging system.
I wondered if that little donut thing was a resister. I had opened up the switch and got full current straight threw from the terminal spade to the contact on the other
side, but only a small amount of power along that curved GEN strip. Interesting how that metallic thing can reduce the current or voltage.
side, but only a small amount of power along that curved GEN strip. Interesting how that metallic thing can reduce the current or voltage.
onefarmer
Well-known Member
- Location
- 6735 S Lowell Rd, St Johns, Mi 48879
When I rewired the 4020 for 12v I discovered the light switch was two in one. A half for each side of the 24v system. I just ran a jumper wire between the two power terminals. Still works all these years later.
Wonder if you could use the 24v switch and do the same as I did?
Wonder if you could use the 24v switch and do the same as I did?
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