Mahindra eMax25L HST blows fuses when starting

[bbocaner]

Hi everyone - this is my first post here, I hope I can learn from some of your knowledge!

My wife's most prized possession is her Mahindra eMax25L HST. About a week ago it started blowing the 40amp fuse that is in front by the battery and radiator when we go to start it. We've been through half a dozen fuses now trying different things and I'm starting to have nightmares about this! I've done a lot of searching on this forum and have found some ideas for troubleshooting, but so far haven't had any luck. Once after replacing a fuse it did start again, a few times, but then it eventually blew that fuse too and we haven't been able to get it to start again since. We don't have a Mahindra dealer anywhere near us and are afraid it might be difficult to get professional help with this, so we're trying to figure this out ourselves.

The key can be turned to run and the instrument panel will light up, but once you turn it to start the fuse blows immediately.

So far, we have:

1. inspected all wires for damaged insulation/fraying. I did find one small wire going to the ECU which had worn down a bit against the engine, but it was barely through the insulation (if at all), and I taped it up really well.
2. Checked the continuity with a multimeter between the negative terminal of the battery and different bolts on the engine and frame. The ground seems to be good.
3. took the lower part of the dashboard off and looked for frayed wires at the ignition switch. It looks good. The upper part of the dashboard I need to get a larger socket to be able to remove the steering wheel first and it also looks like I'll have to reach under there and get a castle nut off the throttle lever.
4. tried unplugging the small separate spade connector from the starter solenoid. It still blew the fuse even without the starter solenoid plugged in.
5. checked for continuity between the spade connector going to the starter solenoid and ground. There was none.
6. unplugged the temperature sensor on the coolant line out of the engine to the radiator. (I read on this forum that sometimes these short out internally)

Are there any other thoughts? Thanks so much for any ideas!

 

[bbocaner]

I should add that there's no noise from the solenoid when turning the key to start. It just blows the fuse immediately.

 

[WranglerX]

From your description of problem, it would appear there problem is between the start switch and solenoid/starter.... Sounds like either a short in wiring or start solenoid/starter failure... Best thing you can do is get wiring diagram and look for a short at any place where a failure may occur.....

Does the fuse blow when key switch goes to glow plug heat position?

Something to try is to disconnect the "start lead" from solenoid (and insulate it), replace fuse and put switch over to start, if fuse does not blow problem found.... IF fuse still blows start a trace back on the wire to the start switch...

 

[bbocaner]

Thank you. There are four red wires going to the solenoid. The main terminal has one large gauge cable that I believe goes directly to the battery, no fuse, and two smaller wires connected to the same terminal, I don't know where they go. Unfortunately, most of the wiring is bundled up inside plastic flex tubing, so it's really hard to trace out. But I would assume there aren't frayed/chewed wires inside the flex tubing. The fourth connection on the starter solenoid is separate and my assumption is this is the one that goes to the ignition key. I did try removing this from the solenoid and insulating it and the fuse still blew when we turned the key.

Unfortunately we've been unable to find a copy of the service manual for sale. There are apparently a couple of different OEM manufacturers for the eMax25 and all the printed manuals I've seen for sale are for the wrong version. billstractor.net has digital downloads for sale of the service manuals but they have a disclaimer that the wiring diagrams in these downloads are illegible and that you shouldn't buy them for that.

 

[ruffdog]

Does your owners manual have a wiring diagram? This would help. The 2 smaller wires coming from the lug on the starter will power switched and un-switched circuits. Even a bad start switch may be the cause.

Being that you have already disconnected the starter solenoid and it still blows, keep disconnecting circuits and trying. Connect the starter but disconnect fuel solenoid, glow plugs, etc and see if it will crank. Do you have relays you can pull?

 

[Minsid]

Something you can do to at least save on fuses while debugging is to check continuity from the fuse terminal to GND. With a 40A fuse that impedance should be above 500 0.3 ohms. That can also tell if it is a perpetual short or one that happens during the starting process. (Though it appears to be the latter)

After that without a wiring diagram I'd have to resort to disconnecting things one by one and checking that impedance.

 

[bbocaner]

No wiring diagram in the owner's manual, unfortunately. There are some boxes connected to wiring in a few different spots on the tractor I think might be relays. I'm really going to have to get the upper dashboard off to be able to follow all of the wires. I'll try that once we get a supply of more fuses.

 

[bbocaner]

Something you can do to at least save on fuses while debugging is to check continuity from the fuse terminal to GND. With a 40A fuse that impedance should be above 500 ohms. That can also tell if it is a perpetual short or one that happens during the starting process. (Though it appears to be the latter)

So, put a multimeter on the side of the fuse terminal that doesn't lead to the battery and on ground? Seeing as it only blows fuses in the start position, I think I'd have to have a helper hold the key in the start position while I did that. That's a good idea, though. Thank you.

 

[ruffdog]

Interesting thread...read to the end:
2012 Mahindra Max 22 Will Not Start, Electrical Problems. Not Safety Switch Related.

It sounds like the Max and eMax are different....the eMax has the additional 40a fuse. ???

 

[ruffdog]

More reading:

Trouble Shooting Emax 22 HP - Electrical issue

Mahindra Emax 22