Alternator not charging warning light

[Laggard]

New Holland TM155 Alternator not charging warning light comes on at full revs but goes off if you trottle back. Why is this please?

 

[Phil P]

New Holland TM155 Alternator not charging warning light comes on at full revs but goes off if you trottle back. Why is this please?

Sounds like the regular is on its way out, over charging as well as under charging can put the light on hence coming on at high revs. It would probably worth sticking a volt meter on if you have one if you’re thinking of keeping running it as over charging can soon damage the battery or worse.

 

[ACEngineering]

Also beware overcharging if battery is under cab, had a case once overcharge and the battery gasses got inside the cab.

 

[Barleymow]

Take it into nacton auto in Ipswich

 

[milkloss]

Might be brush/rectifier cartridge. £20 odd quid swap out when I last did the jd a couple of years ago.

 

[box]

If the light comes on with the engine off and the ignition on, it's probably a rectifier diode.

If the light doesn't come on with the engine off and the ignition on, it's probably worn out brushes.

Confirm it's not charging with a multimeter, then take it off and have it bench tested by your local auto sparky.

 

[Badshot]

I can confirm having a battery overcharge and explode 2 feet in front of your face is no fun whatsoever.
Get it checked, or just stick a new alternator on it.