Needing some help with the electrical system. Long 2460DTC

[Girvin13]

Hello,

I have a Long 2460DTC 4x4 tractor. My late father in law owned it before me. Sometime in its life the alternator was replaced with a standard old school chevy alternator from a late 80's Camaro or similar. It has a built in voltage regulator from what I can tell. The factory regulator is still on the firewall but I do not know if it still works. There are wires going to it.

The problem I have is that my fuel gauge is the only gauge working with any of the switch functions. The gauge lights and headlights work under the specific switch functions. I have checked the fuses under the hood and they all test good. I have the service manual for the 460 series but it does not have the same RPM/hourmeter as the 2460. The 460 was controlled by a drive gear for it.

None of the indicator lights on the right work either. I am thinking they don't have all the wires connected as the new alternator does not have terminals for them. I may have to buy an original alternator. Not sure at this point.
I have the 2460 parts manual but a few pages of the Instrumentation section are missing. If anyone has them to share, let me know.

If I can figure out how to get the gauges working, I am thinking about putting a blade style fuse block in place of the ceramic fuses.

Any insight to my issue would be greatly appreciated.

 

[Roadworthy]

I don't know what was done to add the Chevy alternator but normally everything is powered from the battery. The alternator's only job is to maintain the charge on the battery. Your old voltage regulator should be doing nothing. The wires would have gone to the old alternator to control it. They should be unused now.

 

[WinterDeere]

Sounds like a half-dozen separate issues. The alternator output (or Vreg output) and battery are in parallel, so will be at the same voltage, minus some insignificant wiring voltage drops. Careful about running this rig with battery disconnected, until you figure out what's happening with the regulator(s), or you could quickly blow every bulb and gauge on the machine with a variable alternator output. Keeping the battery connected is a form of regulation, in itself.

As to the indicator lights, it shouldn't be that difficult. Closed-loop system, you just need to see if chassis ground is positive and negative, and check voltage between that and the incoming wire. People get tripped up when they see voltage under no load (bulb removed), and then no voltage with load (bulb installed). This is just evidence of a high-resistance connection, bad wire or bad ground.

More info or familiarity with your particular machine would be needed for more relevant advice.

 

[Girvin13]

Roadworthy,

The battery seems to be charging with no problem. I have 2 or 3 unused wires that are taped up to the red positive wire on the alternator. I would imagine that the taped up wires were from the old alternator as you suspected. I haven't checked to see if the chevy alternator has the internal regulator connected or if the tractor is using the original regulator on the firewall. There are about 4 or 5 wires connected to it. I will try to get some pics this afternoon. Raining at the moment.

My goal is to get the hourmeter/tach and temp gauges working. I am not sure where the tach gets it input from. I would imagine the alternator sends that signal to the tach. The hourmeter is switch controlled. The water temp gauge is not working either. Possible that a hot wire to them is missing or broken.

Winterdeere,

How would I check to see which regulator is being used? If both regulators have wires going to them, where/how could I check?

 

[WinterDeere]

How would I check to see which regulator is being used? If both regulators have wires going to them, where/how could I check?

You could check consistency of output voltage from alternator with a dummy load connected directly to alternator output, and tractor disconnected from the alternator output. An automotive battery tester is going to draw too much, and an incandescent lightbulb may not draw enough for the regulator to work properly, but I'd guess any "dumb" 110V resistive space heater would create a nearly-ideal load for alternator testing. Got some test leads and alligator clips?

Idea is to put a test load directly across alternator, with tractor and external regulator disconnected, and measure voltage while varying alternator RPM. If voltage spikes way above 15 volts when rev'ing the engine, you know there's no internal regulation.

When I was debugging a regulator on my first car, around age 16, I accidentally blew damn near every lightbulb on the car when rev'ing the engine. It was like a super-Nova in my garage, massive flash of white-hot light, and then every bulb excepting one of the dozen in the dash cluster and the map light went out.

 

[Girvin13]

Winterdeere,

I took some pics of the alternator today and noticed a plastic plug covering the internal VR of the chevy alternator. I would presume the factory VR is still being used. There are 3 wires not being used at the moment. You can see them in the pic. The charging system seems to be working correctly. Any ideas on how to get the tach/hourmeter and temp gauges to read correctly? The tach sets at 0 RPMs and the temp sets to the far left as if the engine is cold.

I do not have a wiring diagrahm for it so I can't determine what the wires go to or they monitor.

 

[Grumpycat]

The old voltage regulator should be totally disconnected. I suspect those extra wires were between old voltage regulator and alternator to control the field. This function is performed by the internal Chevy regulator.

The output of a modern excited-field alternator is controlled by the strength of the field. Regulate the field and you get 50-100 times more out of the alternator than you used on the field. These alternators do not have magnets, they use coils to create an excited field instead.

 

[WinterDeere]

Winterdeere,

I took some pics of the alternator today and noticed a plastic plug covering the internal VR of the chevy alternator...

I'm an electrical engineer, so with a wiring diagram I could probably help you figure this out. But since I don't normally do automotive electrical system work, I really have no familiarity with what the various wires there are doing, you'd honestly be better off with any good mechanic than me for that. My work with alternators and automotive regulators was all when I was young, fixing my various old cars, so I've never really looped back and applied what I learned later to any of it.

That said, if you've confirmed the power is being taken off a regulated output from the alternator, you should completely disconnect the tractor's regulator.

As to the gauges, we just need to trace the wiring, and see where it's terminating. Are you sure the gauges aren't already receiving power, but just broken?