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Alternator caught on fire

This is the 2nd time this problem has happen. What would cause my alternator to catch fire or the wires to melt inside??????

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Posted on Jan 02, 2017

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SOURCE: nissan serena alternator

You must test first if your alternator produces output voltage (usually about 13.5V)
A test light is a simple but extrememly useful tool.
If you are trying to diagnose and troubleshoot an electrical problem, sometimes a test light can help you rule out possible causes much more quickly and easily than a DMM (Digital Multi Meter)

Posted on Aug 09, 2008

  • 404 Answers


Hello, I had a Dodge D100 which did the same many years ago, hope this helps. I not only had alternator prob's but my battery exploded too! The alternator has/had a seperate regulator control box and a wire had chaffed which was touching the body causing the regulator box to think Battery totally flat so pushing max amps through the system till bang.
So? If the Ford has the same system or not try looking for reasons to cause a possible charging overload.
Good Luck and Merry Christmas!
Paul 'W'

Posted on Dec 23, 2008

  • 36 Answers


The reason the fuse blows/melts is because there is excessive draw. The other alternator could be wired wrong. Check to make sure the wires are correct gauge.

Posted on Jan 03, 2009

  • 255 Answers

SOURCE: 89 Firebird blown 2nd alternator in a month!!!!!! NEED HELP!!!!

dude i tell you right now you problem is in where you get your alt from
take it back to auto zone get your money back after having these defect units. go to napa pep boys or advanced. get one of there alternators, and have them put it on there tester make sure it is putting out at least 12.35 volts minimum, it will probably be around 14. to 16. volts have battery charged before starting. after starting the car put voltmeter to back alternator elec. post once again. as long as your voltmeter reads above 13.25 volt you are good. hope this helps the situation


Posted on Apr 15, 2009

  • 5 Answers

SOURCE: 81 toyota pick-up. No spark

Check to make sure the main fuse is good. Sometimes those blow when you short out a wire from the battery to the ground on the car *like when an alternators live wire hits ground on the car.
On a 1981 Toyota pickup, im unsure of where it is located, but sometimes they are located in the fuse box, as a big fuse usually a 100 amp or 80amp fuse.. Sometimes they are located along a ground connected to the engine and the frame of the car. This could make it just crank and not start.
Check also to make sure that the engine is grounded, by taking a test light and connecting it to the positive side of the battery, and testing the metal around the motor. Sometimes grounds can break, or when shorted out they can melt. If the motor is not grounded then it will not start. and will just crank.
Hope this helps a little - Jarett

Posted on Aug 17, 2009

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1 Answer

Why does my altinator get so hot

The alternator is over charging or the wire to it is a dead short . If it has an external regulator then replace it . Failing that take the car to an accredited auto electrician to be tested .

Aug 01, 2014 | 1993 Ford F150 SuperCab

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Ground cable caught on fire

This is probably a grounded starter. You are lucky the fuse panels are intact and it is not melting the fusible link. You may possibly have a bad solenoid or someone put the wrong starter solenoid on the vehicle.
Starter solenoids can look the same outside and be different inside. If this is a new vehicle to you, the wrong solenoid may have been installed.

Jun 18, 2013 | Ford Bronco Cars & Trucks

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Installed new battery and starter two days later battery catches fire and melts terminals. why?

I had the same problem occur on an 86 model Nissan truck. It was determined that the alternator was overcharging the battery and caused it to get hot to the point it caught fire. Check the alternator to see if it is overcharging. Sorry to know that happened.

Jun 20, 2010 | 1995 Nissan Pickup

1 Answer

Crossed battery wires on 2001 ford tarus. When this occured the horn beeped and the trunk released as sparks flew. Immediatly removed the cables and ever since then the car has been burning up...

Hi, yes fuses are there to protect what they are made to protect, but when the main power source is crossed, the dc voltage can and will do a lot of damage. I have seen the electrical wiring ignite and burn the auto to the ground! there is a lot of amps in the battery. This is indeed what is causing the alternator to burn out. You have dead shorts somewhere in the wiring harness, wires that are more then likely burned together and touching, positive to negative at times causing these problems to occur. If you can't locate these wires by testing for any hot wires that are grounded, I would recommend getting this auto in the shop. What will happen if you do not, will cost you your auto, could cost you your auto by causing a fire. This is dangerous when something of this magnitude happens. This is not a minor short in the system, it has caused some major damage. I don't mean to freak you out, I just don't want you to have any further damage. Look it over well, and see what you can do. If you cant find the melted wiring, which it will be melted, take it in. Keep me posted on this.
PS Check around the ignition wiring harness as this is where the majority of wires come into. If you can, pick up a manual on your auto to look over the charging circuit as you are burning out alternators. You may find the problem in that circuit. Alternator, battery cables, starter, voltage regulator is built into the alternator, ignition, and so on. You should be in the right area. Good Luck, and keep me posted.

Apr 14, 2010 | 1999 Ford Taurus

1 Answer

1986 Ford Econoline

Has anyone tested amperage output and draw on that cable? While running and while starting? With all accessories on etc? Perhaps a heavier gauge cable would be recommended, and/or at least an inline fuse, to avoid fire.

Dec 23, 2009 | 1986 Ford F 250

1 Answer

My alternator caught on fire through what i think is my voltage regulator it is a 1990 ford bronco inline 6 300 where should i start looking for the problem also the connector goin into the alt. is ashes...

Yes,alwaways replace fire damaged componants. Now, I really don't think the fire was caused by the regulator. When an alternater works at maximum output for an extended period, it overheats and overheats enough to melts soldered connections. Better known as slinging solder. When this happens loose connections go where they shouldn't and a short is created which in turn heats and melts the winding lamination which is what actuall catches fire.Once you replace the Alt. the impportant thing is to find out why yhe old one got so hot. Make sure the charging rate is between 13.6 and 14.2v. Anything less than 23 volts will cause an heating up. This is because the Alt is very, very near full output. Make sure all grounds are good and the battery fluid is at rec, level. Good Luck, Ned

Nov 12, 2009 | 1990 Ford Bronco

2 Answers

Alternator wire that runs to the fuse box melting.

if you have a salvage yard near you go there and find a durango with the same engine as your cut those wires of and your and then rewire it look at the dodge rams as well.

Mar 02, 2009 | 2000 Dodge Durango

1 Answer


Hello, I had a Dodge D100 which did the same many years ago, hope this helps. I not only had alternator prob's but my battery exploded too! The alternator has/had a seperate regulator control box and a wire had chaffed which was touching the body causing the regulator box to think Battery totally flat so pushing max amps through the system till bang.
So? If the Ford has the same system or not try looking for reasons to cause a possible charging overload.
Good Luck and Merry Christmas!
Paul 'W'

Dec 21, 2008 | 1984 Ford F 150

1 Answer

1999 Volvo S80 will not hold a charge

Tricky ... Was the alternator replaced with a 2nd hand one or a new one?

A defective alternator can allow the battery to discharge within a few minutes (the diodes in the rear of the alternator can burn out and cause the problem. The diode pack can be replaced). When this happens recharging the battery only replaces the power in the battery - which drains straight back to earth via the alternator, flattening the battery again - often within a couple of minutes or less.

Does the battery lose its charge when the car is standing or just when the engine is fired up?
If the battery loses its charge overnight, try disconnecting the wiring from the rear of the alternator (also look at the electrical connector that fits into the back of the alternator - look for melting/burning marks which suggest something may be amiss inside the alternator).

Let the car stand overnight with the alternator wires disconnected. Will it start up ok and drive (with the alternator wires still disconnected) the next morning?

You could also try just disconnecting the alternator wires, firing up the car and then driving it -
If the car drives ok without dying out and gets further down the street than it usually does, then it probably is the alternator at fault. The car should drive until the battery drains and has insufficient power to trigger the ignition. You certainly would get further down the street with a charged battery and disconnected alternator than you currently do.

It does sound as though you've had an alternator fault to begin with. If it has been replaced with a 2nd hand unit that unit may also be faulty. Rather than replace parts in desperation, visit an auto electrician's - within a few minutes they will be able to test the battery/alternator output and also identify where the lost current is going. It will be cheaper in the long run to have an auto electrician look at the charging system. It only takes a few minutes.

Sep 14, 2008 | 1999 Volvo S80

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