JD 7800 batterie drain

[Sibley]

I have a JD 7800 (1994) that drains the batteries in about 2 weeks. I have changed the batteries, the alternator, the key switch and the blower switch
to no avail!! Perplexed------Sib.

 

[jaotguy]

pull the positive cable off the battery .... connect a small wattage light bulb in between the cable and the battery ....
if it lights, you have a drain ( not a bad battery ).

now start disconnecting ( or pulling fuses if you have any ) things, one at a time till the light goes out .... also check for "rubbed" through wires by shaking / moving wiring harnesses....

 

[Tx Jim]

On using a test light to find a drain I was taught to remove the ground cable not the positive cable. I was also taught when removing battery cables remove ground cable 1st and on re-installation install ground cable last.

 

[jaotguy]

unless you are in Europe, then the Source to Drain is reversed ...

the reason over here for the neg being the last to connect is usually when "jumping" a dead vehicle . the NEG cable is connected to the block of the engine so if there is any spark , it is well away from the battery and any gasses floating around.....

 

[Sibley]

Thank you Joatguy------When I get some time I'm going with it.

 

[Sibley]

Thanks Tx Jim----another good thought!!

 

[boggen]

your in for a long haul to find the issue if it is in the wiring, might suggest picking up some battery quick disconnect ends. so you are not constantly monkeying around with wrenches to remove cables from battery.

adding to what jaotguy noted, if after pulling fuses and relays to try and track down problem, (googling your tractor to see images) your tractor is large enough, i would assume the tractor has a few different spots were you can disconnect a wiring harnesses. so as to possibly split things up, to see if it drain is say on the engine wiring harness, or cab wiring harness, front dash wiring harness, side dash wirining harness, or other section of wiring harness.

a shop manual for your tractor, would give diagrams of were your wiring harnesses plugs are at. along with detailed info, of what color wire connects to what. to be able to fine tune your search.

 

[Sibley]

Thanks Boggen -----Already have quick disconnects----been do'in the disconnect for 2 yrs. !!

 

[boggen]

last min thought, stinking rodents, mice to other, to simply vibration and insulation rubbing off in very ugly spots you may never be able to see let alone get to.

multi meter or a test light, with aligator clips, to different size pin ends, to test wire harness plugs. different sized solid wire, with dremal sanding bit to round ends of solid wire some. can help get into the female end of the plugs. i have been known to buy cheap test light kits and like. and butcher the stuff for the ends and splice the wires together, to get what i need. it looks ugly, but *shrugs* what ever gets the job done. with tractor battery disconnected, i have butchered a kids toy, for the little 9v battery plug, if i needed to test with a little bit of power, and use of a test light.

if a test light is a LED, be fore warned, it will only light up, in one direction and not the reverse direction.

 

[Tx Jim]

unless you are in Europe, then the Source to Drain is reversed ...

Please explain. Does negative cable on European tractors attach to starter & positive cable attach to frame? Thanks,Jim

 

[jaotguy]

some older euro vehicles used to be Positive ground , most have converted to the negative as we have.

most cars over here have power from the positive to a fuse then a switch then thru the item then to ground .....

Europe goes positive , then fuse , then item, then switch then ground ... ( breaking the ground as opposed to breaking the positive in North America )

either one works well and is safe ( as some of the early tractors over here used to be positive ground ) ....

the safety factor is to reduce the likely hood of sparks near the battery and any explosive gasses .... hence the reason to connect the final "jumper" negative connection to the engine block , away from the battery in case it explodes ....

disconnecting/connecting either at the battery may still create a spark .....

follow the best safety practices as possible and enjoy life ... in this case , both would work fine.

BTW Source and Drain actually show the proper flow direction of electrons ( neg to pos )

we over here think they run from POS to NEG ( in reality it doesn't matter unless you are designing circuits )
:thumbsup:

 

[Tx Jim]

Just for clarification JD 7800 battery cable that attaches to starter is positive and cable to frame is negative.
parts key 1 RE34431 Battery Cable 1 X X X (A) (-)
RE39617 Battery Cable 1 X (B) (-)

parts key 5 RE34430 Battery Cable 1 X X X (A) (+)
RE48982 Battery Cable 1 X (B) (+)

 

[Sibley]

Thank you, thank you, thank you-----Tx Jim Joatguy and Boggen !!

Finally got some time, so I put a light about the size of a license plate bulb between the ground post and ground and it barely glowed, so went to a smaller
dashlight buld which lit up pretty good.
Started pulling fuses and got to the one that said seat. This tractor has a warning on the dash if you get out of the seat when the PTO
in engaged. So I unhooked the little double wire going to the seat pad, plugged the fuse back in, that didn't change anything. This seat
also has many wires going to the air pump and bag in the bottom of the seat. Then I removed the fuse, hooked up the battery cables
and started the tractor. Everything seems to work just fine without the fuse and no battery drain. Sib

 

[jagyzf]

Thank you, thank you, thank you-----Tx Jim Joatguy and Boggen !!

Finally got some time, so I put a light about the size of a license plate bulb between the ground post and ground and it barely glowed, so went to a smaller
dashlight buld which lit up pretty good.
Started pulling fuses and got to the one that said seat. This tractor has a warning on the dash if you get out of the seat when the PTO
in engaged. So I unhooked the little double wire going to the seat pad, plugged the fuse back in, that didn't change anything. This seat
also has many wires going to the air pump and bag in the bottom of the seat. Then I removed the fuse, hooked up the battery cables
and started the tractor. Everything seems to work just fine without the fuse and no battery drain. Sib

Thanks for posting your results, so many times we never hear what was found or how you found the issue.