Electrical question on Mahindra

Still have issue with battery idiot light. Replaced alternator and no change. First, light does not come on when I turn on ignition switch. I think light is supposed to be on when ignition switch is on, and go off when tractor starts. After tractor runs for 15 or 20 minutes the battery light comes on very dimmed. Battery is strong. Any ideas?

I would bet a bad dash panel or ground causing a back feed issue after it is run.

What is your voltage when running?
Should be about 14 once the light goes out.

Thanks

Thanks. I will check it out.

Your issue is a bad panel or bad connection. When you turn the switch on that light should come on and go off when the alternator current is higher.

Unless there is some strange electronic control involved...

The light is a simple circuit, one terminal of the lamp is powered hot from the ignition switch. The other terminal goes to the regulator or alternator, depending on the system used. Look on the alternator for a name, like Autolite, Motorola, etc. Search "xxxx alternator wiring" and you can get a basic diagram of what's in there.

When the ignition is on, and the alternator is charging properly, both terminals of the light are powered equal, so the lamp goes off.

If the alternator is not charging, the power is not being returned to the lamp, so it would be on.

BUT, if the power from the ignition switch was not being supplied (as in a loose connection) the power from the alternator would feed back through the lamp and cause it to glow. If this is what's happening, look for corroded connections, especially if there is a plug together connection that is exposed to rain or near the battery. That lamp is also essential for proper charging, it "excites" the alternator to get it charging. If the circuit is not there, the alternator won't charge properly.

Usually the circuit that supplies the lamp will power other instrument related lamps and gauges. If other problems are showing up, they could be related.

Thanks very much!