Alternator issue

G

GreenhouseGuy

New member
My boss put a new battery in our mahindra 4540. He put it in backwards, hooked the cables up and tried to start it. By the time he called me in to take a look, I have no idea how many times he turned the key trying to start it. Present day, still same battery but I found that it would no longer get a charge from the alternator. I figured he fried something in the alternator so I bought and installed a new one. Checked all the fuses then fired it up. Still not getting a charge from the alternator and I am at the sweetest of my knowledge. Any ldeas?
 
Welcome to the forum.

Connecting the battery backwards can cause any number of problems.

Does the dash have a battery light? Is it on? On some machines, that light being on is actually an integral circuit and could cause things to not work properly.

My initial thought is the voltage regulator may have been fried. I'd guess a new one is about $40. It could be the ECU got fried but let's hope you don't have to replace as they're probably a couple hundred $$.

Other thoughts -
With the tractor running:
Have you measured the voltage coming out of the alternator?
Have you disconnected the battery cable from the alternator to the battery? Does the tractor keep running? If so, the alternator is good. Understand this comes with some risk as you don't then have control over the systems voltage.

Here's a link about general Mahindra electrical problems. Maybe it could provide some insight.

Mahindra Tractor Electrical Problems

mahindrafixspot.blogspot.com mahindrafixspot.blogspot.com

Let us know how it's going and the resolution
 
Yes sir. The battery light is currently on at all times. The voltage coming out of the alternator shows 11.86vdc. Brand new alternator so reading up on it on another source tells me that I may be missing voltage coming into the alternator. I am just not familiar enough to know where the voltage going in is coming from on this tractor.
 
11.86vdc is way wrong. It should be around 14v. Is that with the battery connected?
It does sound like the voltage regulator is shot.
 
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