NEED HELP WITH ELECTRICAL PROBLEM

[Soundguy]

It really depends on his wire setup. .. this is all shear speculation. I'm just going under the assumption that the ammeter is before his fuse box, and that the ammeter both opened internally, and then shorted at least one side of the system to ground..

Since he said he 'bypassed' the ammter by hooking the wires together, and then everything worked ..I'm just guessing.Of course.. there could be 100's of other issues.. we just won't know untill he posts the outcome... or at least.. a wire diagram.

Soundguy

 

[Travis_R]

Thanks fellers.

Through all of this, the main fuse ONLY blew one time. I changed the fuse, THINKING that was the problem. With the new fuse in, thats when we traced the problem to the amp meter.

Even with the tractor RUNNING and both wires hooked to the amp meter (like they should be) we jumped the posts to the amp meter and all the lights and flashers worked normally, BECAUSE the alternator was keeping them on. BUT the needle NEVER moved not one time during all of this, even with a "load" on the electrical system with all the lights on.

Thats what leads us to believe that something internally is burnt out inside the amp meter.

Like I said, the ONLY time I changed the fuse was when I first realized I had an electrical problem- THINKING that the FUSE was the problem- THEN came to find that it was the amp meter.

You know, even the light will come on inside that lights up the amp meter guage. But like I said, its something burnt out inside the meter that makes the charging indicator needle move- Thus NOT completing the electrical circuit to the lights and gauges.

I Truly appreciate the replies.

Travis R

 

[Old Pop]

I also own a used Mahindra 485DI with an electrical problem. My ampmeter doesn't show it is charging either. I do know that a fuse or two is open in some circuits and some of the lights have been damaged. I was wondering if you have a copy of the wiring diagram for this model tractor that you might could post. I think if I had a diagram, I might be able to try and trace down my problems. If not, do you know where I might be able to find a copy of the wiring diagram? Thanks for any assistance.

 

[Travis_R]

Old Pop,

I do have a copy of the wiring diagram in my owner's manual. I have no way of posting it on here though. I don't know how.

What are your problems? I may be able to help you. Do you 'think' you have a problem, or you know you do? THE AMP METER NEEDLE RETURNS TO ZERO, WHICH IS RIGHT ON THE LINE OF THE RED AND GREEN WHEN THE BATTERY IS FULLY CHARGED. Turn your lights on and see if the needle moves to the 'plus' (green) side of the amp meter.

I'm glad that i'm not the only one who has a 485 DI here on TBN. Far as I know, its a total of 3 of us now. A feller named "F350" has one, beside me and you.

Travis R

 

[Old Pop]

Well, the needle never moves and it doesn't charge the battery. As I had posted, the PO (previous owner) didn't take real good care of it and several of the lights are broken, and a fuse or two are open. Also I am not sure if it uses an alternator or generator. I haven't removed the dash yet to check out things behind it. I currently have a 8N project that will consume a bit of my time when I can do some work. BUt I do want to get Big Red back to charging agin. I have a friend who has a newer but smaller Mahindra but the diagram is a bit different as it has some features that mine doesnt have. So that is why I am trying to locate a diagram for it.

 

[gemini5362]

Old Pop,

I do have a copy of the wiring diagram in my owner's manual. I have no way of posting it on here though. I don't know how.

What are your problems? I may be able to help you. Do you 'think' you have a problem, or you know you do? THE AMP METER NEEDLE RETURNS TO ZERO, WHICH IS RIGHT ON THE LINE OF THE RED AND GREEN WHEN THE BATTERY IS FULLY CHARGED. Turn your lights on and see if the needle moves to the 'plus' (green) side of the amp meter.

I'm glad that i'm not the only one who has a 485 DI here on TBN. Far as I know, its a total of 3 of us now. A feller named "F350" has one, beside me and you.

Travis R

Travis when you turn the ignition key to the on position with the lights off and the glow plugs not on when the gauge was working does it move or stay right in the middle.?

 

[gemini5362]

It really depends on his wire setup. .. this is all shear speculation. I'm just going under the assumption that the ammeter is before his fuse box, and that the ammeter both opened internally, and then shorted at least one side of the system to ground..

Since he said he 'bypassed' the ammter by hooking the wires together, and then everything worked ..I'm just guessing.Of course.. there could be 100's of other issues.. we just won't know untill he posts the outcome... or at least.. a wire diagram.

Soundguy

That sounds right and this is all speculation. I am just thinking that if he only replaced the fuse once that it should have blown again if the amp gauge was after the fuse and it was shorted. The Amp Gauge could have blown itself open at the same time it blew the fuse. But I am a bit concerned that he has a bare spot on his tractor wireing that is the problem and only touches when conditions are right. My dad had a pickup you could drive for a day, a week, a month or maybe ten minutes before it blew the fuse for the lights. We finally found that there was a very small bare spot where it went under a seam in the sheet metal of the cab. When it bounced just right from vibrations it would hit the sheet metal and short out. You probably dont want to hear how I finally found it.

 

[Soundguy]

I've not seen too many tractor wire diagrams that place the AMMETER after a fuse. In most cases, the ammeter is placed betweent he battery and the charge/load. I.E. the battery is connected to one sid eof the ammeter, and all the loads and the charge line are connected to the other.. thus you can measure net charge / discharge of the system.

With a fuse between ammeter and battery, you are liable to isolate the battery from the system, which may let the voltage spike onthe load side.. either killing the lamps and gauges or possibly damaging the alternator.

If you place a fuse between the charge/load and the ammeter.. you risk the same.

If you place a fuse between the charge and the load/ammeter, you will isolate the charge unit.. however the tractor should still operate on battery, and show a negative ammeter reading... something the original poster did not report.

If you place a fuse between the load and the charge/ammeter, then you would isolate the load, and none of the tractor electronics should work.. except that if it stayed running when this happened.. then the charge unit should still be able to charge the battery.. ( for instance.. in the case of a diesel with no fuel solenoid.. etc.. )

Out of my 'fleet' of tractors.. i don't see a single one with a ammeter or other indicator downstream of a fuse. As the fuses are generally all contained in the load center... I'm not saying that nobody does it that way.. just that i havn't seen it on the ford/NH units, jd, allis chalmers, and IH units.

Soundguy

 

[gemini5362]

I've not seen too many tractor wire diagrams that place the AMMETER after a fuse. In most cases, the ammeter is placed betweent he battery and the charge/load. I.E. the battery is connected to one sid eof the ammeter, and all the loads and the charge line are connected to the other.. thus you can measure net charge / discharge of the system.

With a fuse between ammeter and battery, you are liable to isolate the battery from the system, which may let the voltage spike onthe load side.. either killing the lamps and gauges or possibly damaging the alternator.

If you place a fuse between the charge/load and the ammeter.. you risk the same.

If you place a fuse between the charge and the load/ammeter, you will isolate the charge unit.. however the tractor should still operate on battery, and show a negative ammeter reading... something the original poster did not report.

If you place a fuse between the load and the charge/ammeter, then you would isolate the load, and none of the tractor electronics should work.. except that if it stayed running when this happened.. then the charge unit should still be able to charge the battery.. ( for instance.. in the case of a diesel with no fuel solenoid.. etc.. )

Out of my 'fleet' of tractors.. i don't see a single one with a ammeter or other indicator downstream of a fuse. As the fuses are generally all contained in the load center... I'm not saying that nobody does it that way.. just that i havn't seen it on the ford/NH units, jd, allis chalmers, and IH units.

Soundguy

I see nothing to disagree with your logic in the above. I am just saying one of two things.

1. If the fuse is not between the AMMETER and the battery a bad AMMETER will not blow the fuse.

2. The blown fuse that started the post either was a one time event that had nothing to do with the AMMETER going bad or Something else is still around to take the fuse out again when he replaces the AMMETER. Depending on how the AMMETER is shunted there is a possibility that whatever blew the fuse took out the AMMETER also.

 

[Travis_R]

Part was SUPPOSED to be here LAST Thursday. Called the dealer last FRIDAY and was told that it would be here tomorrow (MONDAY). I've done got aggravated with that.

Anyway, once its fixed, its for sale for $6600. NOT AT ALL because its "junk" or anything alike because IT IS DEFINITELY NOT JUNK!!! Its a Very, Very solid machine that looks and runs great.

I just feel that someone else can get more use out of it than I can. It will be replaced by small, compact Yanmar tractor. I no longer need a Utility tractor. I can sell the Mahindra, buy the Yanmar with a couple attachments, AND have money left in my pocket. I'm coming out ahead money wise, but I am going to loose a "hoss-of-a-tractor"! Thats the sad part.

I will NEVER "put down" on a Mahindra tractor. They are EXCELLENT machines. Hopefully one day, I can get another Utility type Mahindra tractor.

Travis R

 

[Travis_R]

TRACTOR IS FIXED!!

Thanks for the replies support once again.

The problem WAS the AMP METER. All the lights, flashers, and charging system are working properly. Everything is back to normal.

Just the GAUGE by itself (without tax or shipping) was $30.10. TAX was $2.55 and FREIGHT was $7.50.

TOTAL cost came out to be $40.15 delivered to my door, which wasn't bad at all.

For future reference:

**********1997 MAHINDRA 485 DI AMP METER GAUGE PART # AS OF 1/11/07 IS MAHINDRA PART #5550919R91***********


Travis R

 

[gemini5362]

I am glad that fixed your problem. I do however have some reservations that it has fixed the entire problem. Part of the nature of having a short is that they are very transient. If you have a bare spot in a wire that touched the frame or any bare metal then vibrations might cause it to touch again and blow the fuse again . Let us know if that happens. If It dont then congratulations on your fix.

 

[Fredex]

I do however have some reservations that it has fixed the entire problem..

I've also been thinking about that. First post said blown main fuse; replaced; didn't fix pblm. Later discovered bad Ammeter. Still later, not sure if original fuse was really blown.

If that main fuse did blow, then POSSIBLY a transient dead short with the fuse sustaining an arc long enough to take out the ammeter - or vice-versa. Then could happen again. However, if that original fuse was really OK, then PROBABLY defective Ammeter. But then during my 7-8 years in the '50s/'60s as an electronics tech I saw plenty of weird stuff that didn't seem logical. Time will be the final arbiter.

 

[gemini5362]

Fredex I agree it is hard to tell and shorts are extremely hard to find. I have been working in electronics since 1971 and every time I see a short issue I groan. As I said in an earlier post my fathers pickup when I was younger had a short in the tail lights you could replace the fuse and then you could drive a day or a week or a month or 5 minutes before it would blow again. I checked every wire I could see replaced all the tail light bulbs etc nothing I did found it until I finally got tired of dealing with it. I replaced fuse with a piece of 12 gauge wire and waited finally one day I got smoke coming from the fuseholder and then it was pretty easy to see what happened the wire burnt from the fuse holder down to under the cab. When I replaced the wire I saw that what apparently had been a nick in the wire, when you hit a bump the nick would hit a seam in the sheet metal and short out. I would not recommend that troubleshooting method to anyone You can wind up with big problems from it but I had been working on his truck for 6 months. I would keep it for a week and drive it then give it back to him and the next day he would have a blown fuse. I replaced the wire that burned up and he did not have any more problems.