My trusty 1966 JD 1020 wood hauler has a problem, it is not charging and the charging light now comes on when running. At first I thought it was the alternator as I was not getting an increase in voltage when running above what the battery was producing, so I replaced it. Still not charging so I replaced the voltage regulator as I had no power coming to the field terminal. Still no power coming to the field terminal. When I used a jumper wire from the battery to the field terminal, I saw an increase in voltage. I should have done this first, prior to buying an alternator - live and learn! Thus, the alternator seems to be working. Next, I am going to check for a bad wire coming from the VR to the alternator. What am I missing? Suggestions appreciated. Thanks in advance. Does anyone know where I can get a wiring diagram on the web?
Well, I checked the field terminal wire (green wire) all the way back to the male connector on the wiring harness (plugs into the VR) and I have continuity. I even moved the wires around some in case there was a bad spot that would occasionally appear to be okay...same thing, continuity. I plan to check the other wires as well. Any ideas are welcome. I am wondering if I got a bad VR, despite the fact that it is new. Is there any way to test a VR? Thanks!
SUCCESS! Thanks all for the help. The new voltage regulator that I bought was defective. Once I tried another one, it worked just fine. In the process, I sure did learn a lot about the wiring of this tractor.
