JD 2955 Electrical Questions

[davehartman99]

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]

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]

Ok

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]

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

.

 

[davehartman99]

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]

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]

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

 

[davehartman99]

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]

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]

Thx Tx Jim. That helps a lot