JD 455 Electrical Issue - Low Voltage/Key Switch Board

[bthoffman]

Hi guys,

New to posting but have used this board many times to fix issues with my 1999 JD 455.

I'm currently diagnosing an electrical issues that seems to be related to my key switch and board, but could be something else as well.

Tractor ran normal then seemingly out of nowhere when trying to start, dash lights come on, go off, then dead. Turn key off, then back on, nothing, no dash lights, nothing.

Replaced key switch and board with correct module for my later model year, problem solved. After about 4 cuts, same thing, when trying to start, dash lights on as normal, solenoid fires as normal, then at some point before firing up it dies.

Replaced key switch and board again, fires right up. About 4 cuts later...yep, you guessed it, died again...and that's where I stand today.

Now, I did some more digging using my tech manual and found that my battery is good (12.8V) and good power all the way through the key switch board (control/fuse module) to terminals 2 and 6 without the next wiring harness attached (i.e., fuses good, key switch good). But when I connect the power connector harness to the control/fuse module (X1) the voltage across the system drops way down to about 3.8-4.0V then slowly climbs to about 6V after minutes of sitting there. My dash lights glow dim and a bit brighter but obviously not enough voltage to do start the tractor.

Anyway, could this be a short in the wires after the key switch board? A blown board (again?) or what?

Any help is much appreciated!

Thanks,
Brian

 

[JerryK]

Something like this needs to be approached with the old volt meter / electrical diagram thing. There are lots of things it could be. Bad fuse holder, bad [ intermittent ] battery cables [ damaged inside from battery fumes ], loose cables [ both positive and frame ground ], bad solenoid, loose or damaged wiring, bad safety switches in the starting circuit, etc..... Hard to diagnose via the internet. Sorry, and hope you get her running.

 

[Zebrafive]

As suggested in JerryK's post; start with the battery cables. Clean both ends of the positive and negative cables. Clean any grounds for the harnesses, with a tech manual they should not be hard to find.

 

[Kish318420]

Don't forget about the grounds also, check everyone of them. look at the rear, middle front of the frame on the tractor.

 

[Richard001]

Hi guys,

New to posting but have used this board many times to fix issues with my 1999 JD 455.

I'm currently diagnosing an electrical issues that seems to be related to my key switch and board, but could be something else as well.

Tractor ran normal then seemingly out of nowhere when trying to start, dash lights come on, go off, then dead. Turn key off, then back on, nothing, no dash lights, nothing.

Replaced key switch and board with correct module for my later model year, problem solved. After about 4 cuts, same thing, when trying to start, dash lights on as normal, solenoid fires as normal, then at some point before firing up it dies.

Replaced key switch and board again, fires right up. About 4 cuts later...yep, you guessed it, died again...and that's where I stand today.

Now, I did some more digging using my tech manual and found that my battery is good (12.8V) and good power all the way through the key switch board (control/fuse module) to terminals 2 and 6 without the next wiring harness attached (i.e., fuses good, key switch good). But when I connect the power connector harness to the control/fuse module (X1) the voltage across the system drops way down to about 3.8-4.0V then slowly climbs to about 6V after minutes of sitting there. My dash lights glow dim and a bit brighter but obviously not enough voltage to do start the tractor.

Anyway, could this be a short in the wires after the key switch board? A blown board (again?) or what?

Any help is much appreciated!

Thanks,
Brian

Brian,
Welcome to TBN
:welcome:

Richard

 

[bthoffman]

Thanks everyone! I do have the wiring diagram for the tractor and will get to work looking at all the connections. I appreciate all the advice!!

 

[bthoffman]

Thanks again to everyone for the help. It turned out that I had 12.8V at the terminals after the voltage drop so it turned out to be an issue with the battery to clamp connection. The bolt that secured the clamp had a bunch of orange/white colored dust on it so I cleaned up the inside of the clamp, the terminal heads themselves and replaced the bolt and the JD455 fired up like a champ. Funny thing is that the inside of the clamp itself looked great, no corrosion to the naked eye. I sanded it anyway just to be sure but just goes to show that corrosion could be easy to miss!

Also, I'm still not sure why replacing the key switch board the last time "fixed" the problem temporarily but I feel much better with this solution. Thanks again!

 

[Richard001]

Glad you got your tractor going again and thanks for posting the fix.

Battery terminal corrosion is rater common, especially if the terminal bolts are not real tight.

Richard

 

[Kish318420]

Because normal practice is to disconnect the battery before doing any electrical repairs in case you drop a toll and short something. So the connection was temporary cleared of corrosion/oxidation.