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2012 Jcb 3cx erratic tach and battery light buzzer staying on

Jcboffset214 · 2023-02-15 18:25

Hello, I have a 2012 Jcb 3cx last of serial 2011738. I replaced my alt awhile ago when battery light was on and buzzing. I noticed the two small wires were rubbing and arcing off alt to each other, which I did fix. Ever since then, my tach has been erratic and battery light and buzzer will sometimes stay on for hours before turning off. Battery buzzer and light seem to turn off in the morning after startup, but stays on later in the day when machine turned off then back on. Tach is always erratic. Any idea what can be causing this issue?

Replies17
  1. #1hookedondiesel2023-02-17 08:36

    Have you put a volt meter on the battery to see if it is charging? test the voltage before starting and during.

  2. #2Jcboffset2142023-02-20 12:23

    Yes. Alt dosent seem to be charging while battery light and buzzer are on, but tach is either not working at all or bouncing. Alt does seem to be charging intermittently

  3. #3Jcboffset2142023-02-20 12:24

    Tach is not working or bouncing no matter if alternator is charging or not

  4. #4hookedondiesel2023-02-20 12:30

    That doesn't say much...what is the voltage before starting and after starting and running on your meter. The tach could be another story.

  5. #5hookedondiesel2023-02-20 12:31

    Double post.

  6. #6Jcboffset2142023-02-20 12:36

    Just re tested and I am getting over 14 with tester off the back of the alternator with the battery buzzer and light still on

  7. #7Jcboffset2142023-02-20 12:46

    7.84 off w post. 0.45 off d+ post when tractor is off 8.99 off w post. 14.33 off d+ post when tractor is running

  8. #8Jcboffset2142023-02-20 12:50

    Battery light and buzzer seem to turn off quicker than normal after the tractor is warmed up after poking the two posts with the tester

  9. #9hookedondiesel2023-02-20 13:02

    Sounds like you have a bad ground, check and clean both battery post's, maybe also a bad ground cable.

  10. #10hookedondiesel2023-02-20 13:04

    You should have 12.5 volts off, and 14.5 volts running.

  11. #11Jcboffset2142023-02-20 13:57

    I’ve checked and cleaned grounds and checked cable, still same problem

  12. #12woodfirst2023-02-20 20:52

    A very similar thing happened to me. Remove and clean your solenoids particularly Buzzer solenoid. They are all mostly the same. Change them around and see if the symptoms change. I believe mine was a bad alarm solenoid

  13. #13Jcboffset2142023-02-20 21:03

    Do you mean relays, not solenoids?

  14. #14woodfirst2023-02-21 08:11

    yes. Relays adjacent to fuse box

  15. #15Jcboffset2142023-02-21 11:47

    Tried that too, no success

  16. #16hookedondiesel2023-02-21 12:57

    Replace the ground cable.

  17. #17karlos5512024-07-18 18:20

    Had the same issue the other day was a wire from the back of the alternator where the plastic had stripped from the wire and caused a ratic short from wire vibration wire to hit the block