JD 2955 Electrical Questions

davehartman99 · Apr 11, 2022

I have a JD 2955 where I replaced the lights on the fenders with 36-Watt equivalent PAR36 12 volt bulbs. The problem is the wiring harness was rerun by the last owner so it doesn't go to a switch to turn on, they are always on and I will fix that. However, I have a hot line going to the lights and they won't light? I wired 2 bulbs together and then connected them with a single wire to the hot and another to the return, there is no ground. I am perplexed on why they won't light with a hot and return there? Do I need to add a relay and if so, what size/type? Or do you have to wire them individually each to a hot and return or is a ground required even though the lights have no connection for ground on them? Any help is appreciated.

LittleBill21 · Apr 11, 2022

link the lights. all lights require a ground and a hot. if there is no ground wire. they expect the ground via the mounting bolt. generally with a star washer.

davehartman99 · Apr 11, 2022

Ok

LittleBill21 said:
link the lights. all lights require a ground and a hot. if there is no ground wire. they expect the ground via the mounting bolt. generally with a star washer

Ok I figured it may need a ground. I will try that and see if it works. Thanks

WranglerX · Apr 11, 2022

I am perplexed with the term "return" as you use it..... Typically a return CAN BE A GROUND..

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davehartman99 · Apr 13, 2022

So there are two wires going to the light. One is the hot, the second is the return to complete the circuit. Those are there and no light. However, on the harness, there is also a green ground wire as a third wire that is similar to the return except that is supposed to be grounded to metal and it isn't currently. I will try to ground that to metal and see if it works. I don't think it makes a difference but maybe it does. Since I have power in the one hot wire that I confirmed, I am perplexed as to why it wouldn't light without the third green wire grounded but maybe that is the problem. We will see. If not, then wiring both light hot wires together to the one hot harness wire and both return wires together to the one return harness wire may also be an issue and I can try just doing one light at a time. For a regular bulb none of the above should matter but with LED lamps, maybe it is different, hence the ask.

Roadworthy · Apr 14, 2022

If you're using LED bulbs polarity is important. They will probably not work if connected backward. If they are twelve volt bulbs they will need connected in parallel. That is the plus terminal on one to the plus terminal on the other and supplied by the positive battery terminal. The negative terminal on each should be connected to ground or the negative battery terminal. If they have three terminals they are probably used as headlights so you will have a high beam terminal, a low beam terminal, and a ground return on each bulb.

davehartman99 · Apr 14, 2022

That helps a lot Roadworthy, thank you for the info. That may work. Will let you know.

davehartman99 · May 2, 2022

So got the lights working, thank you all for the help. Rewired just about everything. Have a question still. I believe the circuit board was fried and the prior owner rewired everything which was stupid but cheap. Rather than mess with it replacement-wise, I reran all new busses and have everything working from a switch panel that also shows the voltage. However, the RPM gauge isn't working and I wanted to get that on a separate gauge I can mount nearby to show it instead. Any idea on how best to wire that in? This is a JD 2955 tractor so I can try to find the wires for it behind the board but won't be easy. Is there an easier way to do it direct?

Thanks

Tx Jim · May 2, 2022

Tachometer sensor is located on LH front of engine. Sorry I don't know color(id ) of wiring but JD tech manual should contain wiring colors. Printed circuit board on JD 50 & 55 series utility cab tractors had a long history of failure

davehartman99 · May 5, 2022

Thx Tx Jim. That helps a lot

Tx Jim · May 5, 2022

You're welcome. I don't envy your task of sorting out that wiring harness that resembles a spider web when viewing in tech manual

davehartman99 · May 9, 2022

So going to run a tach direct from the alternator. Heard that is the best way to get it on a diesel tractor. Not sure which side to attach it but if anyone knows that would help, otherwise, I can find online. I assume it is the hot side where the battery is attached +. Thanks

davehartman99 · May 10, 2022

Since I read that the JD 2955 has many problems with the circuit board of the main bus burning out and that was most likely why the prior owner rewired a ton of stuff over fixing it, I also decided to bypass it entirely, and create new bus lines to make everything work. In the picture, you can see the new bus running at the top of the cab direct from the lights/fans/etc. to make everything work with a switch panel that also shows the voltage. It also has 2 USB ports and a cig lighter. Ran a new line directly from the battery to there and wired it all up. Taped up all wires into a bundle to make it look like a bus and used holders to make it clean. As for gauges, I am adding a tac / hours direct to the alternator, using a new fuel gauge direct to the sensor, and putting in two idiot lights for the oil pressure and water temp. Once done, I should have everything replaced with the exception of the ignition which works as-is. Not perfect but cleaned up all the mess there was before and made it clean and everything is working now. Thanks to all for the help.

Tx Jim · May 11, 2022

Your wiring appears to be an improvement over JD's failure prone circuit board.

davehartman99 · May 19, 2022

So I think I am just about set with the JD 2955 wiring. I even got an external Tachometer to work well with the signal wire coming from the sensor. The only question I have is what is the average RPM for the tractor at idle? I assume it is around 700 RPM but can't find anywhere that states what it is normally? If I can get that set right, then the tach will perform correctly as gas is applied. Thanks