644E Alt/low volt light bypass

[Merlejoe22]

Sorry I originally posted this in the wrong place. I Have a 644 Deere loader and its original engine swapped out for a 770 Deere from an old grader long before I bought it. the problem I'm having is the alternator and caution light is on in the dash consistently. I'm looking for the circuit to figure out how to bypass the light or make it functional again? I thought their might be a wire that goes to the alternator that wasn't hooked up but there was only one free wire coming from the harness there and connecting it to ground or the positive alt feed did nothing. Anybody know how this works or ever worked on this system/light or have a wire diagram on the machine that could be useful? Machine is old and some of the circuits have been jerry-rigged so I'm open to suggestions.

 

[Merlejoe22]

also. it is the 1989 644E wheel loader model

 

[mg2361]

Welcome to HEF Merlejoe22! Model years mean nothing in the Deere world. Need a serial number to get accurate information. Post a picture of the lights that are on as well as a picture of your alternator.

 

[Merlejoe22]

Welcome to HEF Merlejoe22! Model years mean nothing in the Deere world. Need a serial number to get accurate information. Post a picture of the lights that are on as well as a picture of your alternator.

Thanks for the welcome mg2361 ! I'll Get the vin today and a picture of the lights.

 

[Merlejoe22]

Here is the
Loader VIN# DW644EB517895 and the picture of the light

 

[mg2361]

Can you get a picture of the serial plate. The number you gave is not in the system. How about a picture of the alternator since there are 3 different alternators for those machines.

The first thing we need to establish is - is the alternator charging? What is the voltage measured across the battery with the engine running. What is the voltage measured at the battery post of the alternator engine running?

 

[Merlejoe22]

My machine has no serial plate left on it. the serial number I gave is off an old insurance card and unfortunately is all I have .

1. I removed covers and tested the batteries at the source machine running and the output was 14.1volts
2. Tested output direct to alternator 14.3.
But to bae fair when I tested the batteries the machine was still warming up wich could allow for the discrepancy
The alternator is an aftermarket but here is a picture

 

[mg2361]

That alternator is not one of the options. Two things. Your serial number by the last six digits tells me you have a 544E. Take a picture of your engine serial plate. It should be behind the fuel filter. That will clear things up. Also give me a picture further out from your alternator so I can see more of the wires. Also take a picture of the two posts next to the battery post of the alternator. I would like to know what letters are stamped in the housing next to those posts (ie: EXC, D, GND, etc).

 

[Merlejoe22]

That alternator is not one of the options. Two things. Your serial number by the last six digits tells me you have a 544E. Take a picture of your engine serial plate. It should be behind the fuel filter. That will clear things up. Also give me a picture further out from your alternator so I can see more of the wires. Also take a picture of the two posts next to the battery post of the alternator. I would like to know what letters are stamped in the housing next to those posts (ie: EXC, D, GND, etc).

View attachment 208630

Trying to be as informative as I can.. The machine is definitely a 644E. the serial number I gave could be wrong as it was old paperwork it came from. As I said in my first post the motor that’s in it now is out of a JD770 grader. It does have a tag but I don’t think that it’s going to help with this. The original motors sensors have been bypassed out with jumper wires ie. water/oil she now has mechanical sensors for that. I’m including two more pictures of the alternator further out. Original harness colours I think you can see fairly clearly. I also found a number stamped on the frame by the Center pins I’ll post that as well just in case it helps. Thanks for your patience.

 

[mg2361]

Try disconnecting the tan wire to see if your light goes out. Rewire per below.

 

[zlssefi]

I could be totally wrong here. Most larger loaders are 24v systems. Would I be wrong to assume that the batteries are hooked up incorrectly, supplying the machine with 12v instead of 24??

 

[Merlejoe22]

I thank you very much mg2361. I rewired it to like you said and the light is out along with the caution light. all the other functions working properly

 

[Merlejoe22]

I will be fixing and reconnecting the black ground as soon as I get a chance.

 

[mg2361]

the light is out along with the caution light

Glad to hear it!

Most larger loaders are 24v systems.

That particular loader is a 12 V system.