john deere charging problems

bringing a 301a back to life for a friend of mine. having electrical issues. alternator not charging. it appears to be a prestolite alternator. not real familiar with this critter. heres what i have. with the battery hooked up and key off, both the oil pressure lamp and the charging lamp are lit. on but not super bright. turn key to on position, charge lamp goes out, oil lamp gets very bright. heres a couple pics.

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if you disconnect the oil pressure sender wire from the sender, both lamps go out with the key on or off.

the sender is a green wire coming out of the harness that has the end spliced on it. heres a pic

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on to the alternator. not sure if any of the wires are hooked correctly, as none of the terminals are marked. it is a jd reman alternator. there are 5 terminals on the alternator. the 12 oclock terminal is a blade type connection. at 3 oclock, 5 oclock 7 oclock , and 9 oclock are post terminal connections. the battery hot is hooked to the 7 oclock terminal. when hooked up, the 9 oclock terminal becomes hot, and the wire hooked to it powers up the two dash lamps. disconnecting it shut off power to the lamps. the 3 oclock terminal is hooked up, but not the 5 oclock terminal. neither 3 or 5 have power when the battery is hooked up. all the post terminals are the same size. heres a pic.

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nothing under the dash seems to be butchered or spliced

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there is one extra wire that is not hooked to anything, but seems to long for the alternator harness. the tractor does not have any lights on it.

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any one know what the identity is for the terminals on the alternator so i can trace the wires back? or any ideas as to whats going on? tia

also, i did take the alternator to the local napa to see if they could test it, but the do not have the pig tail to hook it to their tester. may have to take it to jd and see if they can test it.

All I can tell you is,I had a charging issue with mine several times over the 33 years or so that I had it. I changed the regulator two or three times and that was the problem all but once. I had to put a reman alternator on it once. The starter shop here couldn't test one of those either.
The regulator is up under the dash on the right hand side as you're on the seat. Just a little thin square job.

Remove that alt. and the regulator under the dash and toss it all in the trash,,then go to Auto Zone and get a one wire Delco alt. use the battery wire that came to the old alt. and forget the light,,you can make the light work but it's not worth the effort,,you can tell if it's charging by touching your knife blade to the rear bearing housing, if it has magnetism it's charging..

The one wire alt. is not a bad Idea,but if you want a wiring schematic I have one,my alts. on my 301 and 1520 are different than yours,they have the VR on the alt.I had a problem a couple years ago with mine and it was the VR,yours seems to have a short some where in the system because the lights should never be on with the switch off. My email is [email protected] send me a E-mail and I'll send you some pics. of the wiring system.

Tim told you right get rid of the junk this a ploys to Motorola also

Ditto what Tim &amp; Kent stated. Trash can the Motorola alt &amp; reg.

Hi Glennster
As you didn't listen to the you should of let somebody else do it advice L.O.L.I'd say if you got no field/road lights fitted and it only needs to start, charge and have an oil light and gauges. Rip that whole loom off that looks like rats have spent the morning playing with it.
Put an internal regulated alternator on and build a new loom.

I have had tractors here like that with 40 year old wiring, 30 clowns over the years messed with it that had no clue. Then been the guy thats told to fix it cheap. There usually is no cheap you find one problem fix that, move another wire doing it and find the next short or break. Starting again saves a lot of time and frustration. I now do the same with truck and trailer wiring if there is insulation starting to fall off and tape and junk connectors every 2 ft. Doing that stops the problems dead then it's only bulbs going once in a while. I got some used to come here twice a year, now it's fixed right I never see them. I had the hassle because guys wanted to save a few $ that didn't work for either of us in the end, now we are both happy. A few even said why didn't we do that first time! "You didn't want to spend the money the first time", but spent it 3 times in the end L.O.L
Regards Robert

http://www.prestolite.com/productinfo/alternators/8HA2009KA/8HA2009KA_wiring.jpg

I think this is the one you have, but not sure. Motorola makes so many different applications it's difficult to tell.

I agree with others, it will be much cheaper and easier to change it over to a Delco. If you want to keep the dash light, go with a standard 10SI. You can but the pigtail harness at the auto supply. Or go with the one wire.

sounds like switching alternators is the best choice. this tractor uses a 5/8 inch wide drive belt. i do like the hitachi alternator, i think its the 14255 unit. but i dont think the drive belt will work being its so wide. will the driven pully off the motorola/ prestolite work on the hitachi alt? i did a 12v conversion on one of my farmall ms with the hitachi and the 1/2 inch belt just fit. the 10si also runs the smaller belt.

If you like I have the wiring diagram for the JD 1020 tractor which is the AG version

thanks steve, i already see one wiring issue, the black ground wire at the 3 ocklock position should be on the ground terminal at the 5 oclock, it is hooked to the ac tap terminal. i did pull the vreg out, and i can see thru the epoxy something shorted internally in the regulator. i called the jd dealer and they can test the alt, so i will run over tomorrow and have them test it, then check prices and go from there.