# 40 amp fuse keeps blowing .Any ideas where to start?



## Kirby (Aug 16, 2020)

I have a little 40 hp mahindria pst. The other day it quit so I found a 40 amp fuse blown .replaced it and it ran for about 20 minutes before blowing again ...i I immediately tried replacing it and it blew with the key off.
Looked all over for a bad ground or wire with no luck . And ideas what would blow a fuse with the key off ?


----------



## bbirder (Feb 26, 2006)

Look at schematic. What does it say that fuse is for? Perhaps short in ignition switch?


----------



## Kirby (Aug 16, 2020)

I did and the starter,starter seloniod,key switch, heater and alternator are all on the same circuit.


----------



## bbirder (Feb 26, 2006)

Does your manual call for a slo-blow fuse. Thats special and cant be replaced with a reg fuse.


----------



## clark james (Jan 15, 2020)

From the ignition switch, start pulling one wire at a time while checking with a meter for a ground. If no shorted circuit is found, the ignition switch itself may be faulty. Good luck.
sarge41


----------



## Groo (Jan 17, 2020)

You e got a decent sized wire shorted to ground. Look between the switch and the fuse.


----------



## bbirder (Feb 26, 2006)

Kirby,
lets quit chasing our tail. Do have a schematic of the starting circuit or not? If you do please post a pic of it. This will help us help you! I have a hard time believing the starter heater and alternator are all running on the same 40 amp fuse. And above all else please post if you fix the problem and not leave us hanging trying to solve your dilemma.


----------



## clark james (Jan 15, 2020)

I have never seen a starter on a fuse, but my experience is with American stuff, so what do I know!


----------



## Hacke (Feb 22, 2011)

clark james said:


> I have never seen a starter on a fuse, but my experience is with American stuff, so what do I know!


They exist, but 40A? No.


----------



## bbirder (Feb 26, 2006)

He should have a starter relay between the switch and starter. That is why I asked him to post he schematic he was looking at.


----------



## bbirder (Feb 26, 2006)

There is a very good post about similar problems with Mahindra. This would be good info for all to read.

https://www.tractorforum.com/threads/mahindra-max-26-xl-wont-start.32872/


----------



## Jay Jordan (7 mo ago)

I also have 4035 that continues to blow the 40amp fuse. I blew the original factory fuse after doing I did 2 thing: 1. Installed a new battery(old battery was just getting weak) 2. Cleaned the engine compartment (lightly with water, trying to be extra careful not to soak any electrical connections)


----------



## Jay Jordan (7 mo ago)

After reading this forum I may have found my problem as I have been replacing the fuse with ones bought at AutoZone. The do not have "slow Blow" written anywhere on them. I have some Slow Blows on the way thanks to Amazon. I have replaced multiple fuses but all have been bought at AutoZone. They seem to blow when the tractor decelerates as I let off the accelerator to change gears or get ready to move the shuttle shifter. Hopefully I'm just using the wrong fuses and the Slow Blow ones will fix my problems. Any thoughts will be greatly appreciated. I'll update as I know more.


----------



## LouNY (Dec 15, 2016)

Looking at the schematic you have posted,
Starting at the 40 amp fuse, follow the heavy dashed line that is the power circuit for that fuse.
Most of the tee connections have another fuse so if they are good it's not those circuits.
I would look at the wiring especially to your alternator.


----------

