Battery light constantly on (and low voltage on gauge)

Steeda90GT · 10-05-2008, 12:15 PM

I was driving home from work and noticed my battery light flickering on and off. Once I got home I shut it off and started it again. Now the battery light on the cluster is constantly on and the volt gauge reads pretty low (Im pretty sure the stock volt gauge is an idiot light anyway, on and off...right???)

The previous owner put the battery in, so I have no clue as to how old it is. I've owend the vehicle for over 2 yrs now. I cleaned the battery terminals REALLY well because there did appear to be some corrosion.

So do I need a new battery/alternator, or both?

*gavin* · 10-05-2008, 01:28 PM

volt gauge?
Explorer's have an ammeter. It displays the amperage
When the gauge is in the middle, it means the battery is neither charging nor discharging.

When the ammeter goes low, it means the battery is dischaging.

If the ammeter stays low, it's possible the alternator is crapping out.

as for the battery light... I dunno about that one.

With the vehicle shut off, check the voltage on the battery with a multimeter. It should read over 12 volts.

Then start the truck, with ALL accessories turned off, and read the voltage again. It should be at around 13v (sometimes I see as high as ~14 on mine).

if voltage is low with truck running and accessories off, get the alternator tested.

Steeda90GT · 10-05-2008, 05:28 PM

Pardon my lingo, I'm a Software Developer, not a mechanic so I just kind of make things up along the way.

So what is the purpose of the battery light on the cluster? Does it come on when the volts are low and the alternator isn't charging properly?

I also noticed the belt tensioner looked bad. The entire assembly appears to be loose..and when the truck is running, it wobbles.

**Blee1099** · 10-05-2008, 05:43 PM

I would suspect the alternator? Does the tach bounce or any of the other gauges? I would take it to Advance auto or similar place and have the alternator tested. Grab a multimeter (digital one if you have one) and place it on the battery and start the engine and have someone keep the rpm's at about 1500-2000 constantly. See if the voltage drops below 13.8. Another thing you can do is start the truck and pull the negative terminal. If the truck dies, then your alternator is shot.

*gavin* · 10-05-2008, 06:02 PM

maybe the battery light means voltage is low?
and the ammeter would read low if the battery was discharging for whatever reason (ie, the alternator isn't providing enough juice to keep the battery charged and run the vehicle).

I would still HIGHLY recommend, first thing you do, is check the voltage, as I mentioned in my first post.

First check the voltage between the battery posts, with the engine NOT running. It should read around 12.5 or so.

Now, start the truck, leaving ALL accessories turned off. At idle, the reading should be over 13... 13.5'ish is where it most likely goes.

My guess, is that the battery light comes on, because the battery is below a set voltage threshold. It stays on, because the alternator isn't providing enough juice, or because the voltage regulator is toast and isn't providing the correct voltage.

Either way, it would be the alternator.

TheJackal · 10-05-2008, 09:29 PM

The charging indicator ("battery" light) is controlled by the regulator. If the light is on, it means, as stated before, your battery isn't being charged.

Take care of this ASAP, to avoid being stranded with a dead battery.

fixxxer · 10-05-2008, 09:48 PM

The ALT light will come on if the alternator's output is too low. If your idler/tensioner is going bad, you could be merely dealing with belt slippage and that will cause your system to not charge the battery.

*corkey* · 10-05-2008, 09:52 PM

if the belt appears to be wobbling , and the whole thing is loose , i bet the belt is not turning the alternator enough to charge the battery properly cause the belt is slipping,,
fix the loose parts first,

Steeda90GT · 10-06-2008, 09:20 AM

Yes that's what I was thinking as well because the tensioner pulley does appear to be wobbly. I removed it and it looks like the whole unit is seperating.

I'll try that first (only $40) and see if it works. If not, then new alternator. The idler pulley looks good and is spinning nicely (although the bearings are a little noisy)

Cobraguy · 10-06-2008, 09:26 AM

Quote:

Originally Posted by gavin

volt gauge?
Explorer's have an ammeter. It displays the amperage
When the gauge is in the middle, it means the battery is neither charging nor discharging.

Sorry Gavin, but that's not correct. Both my 95 and my 99 are VOLT meters. In fact, I can't remember Ford using an Ammeter in quite some time now.

4x4firefighter · 10-06-2008, 09:41 AM

ok i got on to ask this very question. i just started having same issue. i replaced battery and instaled heavy duty altenator (all the dam lights). and it still does this! when it reads low volatage boys she is next to stalling out!!!

if the vehicle is moving or u are above about 1200 RPM she is fine. its idling or stoping at a red light and everything dies down and almost stalls the car out, lights go real dim, etc......is the 1st guy have the exact same situation?

Steeda90GT · 10-06-2008, 12:13 PM

OK, So I just came back from Vatozone and they tested my alternator. It failed.

So I guess I'll pick one up. Where is everyone getting their alternators from? Vatozone has a new one for $189.99 that has a lifetime warranty. They also have a rebuilt one for $159.99 with a lifetime warranty as well.

4x4firefighter - mine just had the battery light on cluster and very low reading on the "volt meter" lol

The truck still ran fine.

*gavin* · 10-06-2008, 12:37 PM

Quote:

Originally Posted by Cobraguy

Sorry Gavin, but that's not correct. Both my 95 and my 99 are VOLT meters. In fact, I can't remember Ford using an Ammeter in quite some time now.

huh... I always assumed it was an ammeter.
since it never moves, regardless if the voltage is at 12v or 14.5v.

Only time it drops is when I have lights on, heater full blast, rear defrost on, and it's in drive with my foot on the brake. But even then, voltage is still at over 12.

99xlsdude · 10-06-2008, 09:54 PM

About a year ago, I got a rebuilt one with a lifetime replacement warranty from Pep Boys for $120.

Steeda90GT · 10-07-2008, 07:52 AM

Pep Boys quoted me $170 for the lifetime warranty one. I think the alternators are different between the SOHC and OHV, right?

Steeda90GT · 10-07-2008, 07:53 AM

BTW - the $75 eBay ones are damn tempting..

98formulaLS1 · 10-07-2008, 08:33 AM

Quote:

Originally Posted by 4x4firefighter

ok i got on to ask this very question. i just started having same issue. i replaced battery and instaled heavy duty altenator (all the dam lights). and it still does this! when it reads low volatage boys she is next to stalling out!!!

if the vehicle is moving or u are above about 1200 RPM she is fine. its idling or stoping at a red light and everything dies down and almost stalls the car out, lights go real dim, etc......is the 1st guy have the exact same situation?

this can happen when you purchase aftermarket alternators. There is a design flaw in the alternator. The problem is that when you truck is idling, and the serpentine belt is running much slower, it's not spinning fast enough to charge your battery during idle.

*gavin* · 10-07-2008, 10:22 AM

Quote:

Originally Posted by 98formulaLS1

this can happen when you purchase aftermarket alternators. There is a design flaw in the alternator. The problem is that when you truck is idling, and the serpentine belt is running much slower, it's not spinning fast enough to charge your battery during idle.

yup.
when buying a higher amperage alternator, you need to find out how many amps it puts out at idle.
all alt's I've seen, are labeled with the maximum amperage output; which, of course, will not be seen at idle. Some of these put out the same amps as stock, at idle, some are even a bit lower.

Basically what I'm saying... check the idle output when purchasing a high amp alt, do NOT buy it because it says "300 amp!"

Steeda90GT · 10-11-2008, 07:45 PM

UPDATE:

OK - I decided to buy a reman unit (lifetime replacement) for $129.99. I also installed a new belt and a tensioner (the original one was starting to split.

Everything is great, no more battery light on cluster and my "volt gauge" isn't reading low anymore!

kgbrgv · 10-13-2008, 09:52 AM

I have a similar problem. I have installed new battery and alternator. The volt meter is low and warning light is on. What next.

10-05-2008, 12:15 PM	#1
Steeda90GT Wannabe Elite Explorer Central NJ 99 Sport Join Date: Jul 2006 Posts: 448 Vehicle Specs (Original Poster)	Battery light constantly on (and low voltage on gauge) I was driving home from work and noticed my battery light flickering on and off. Once I got home I shut it off and started it again. Now the battery light on the cluster is constantly on and the volt gauge reads pretty low (Im pretty sure the stock volt gauge is an idiot light anyway, on and off...right???) The previous owner put the battery in, so I have no clue as to how old it is. I've owend the vehicle for over 2 yrs now. I cleaned the battery terminals REALLY well because there did appear to be some corrosion. So do I need a new battery/alternator, or both?

10-05-2008, 01:28 PM	#2
gavin Elite Explorer Anchorage, Alaska '97 Explorer XLT AWD 5.0L Join Date: Sep 2002 Posts: 3,047 Vehicle Specs	volt gauge? Explorer's have an ammeter. It displays the amperage When the gauge is in the middle, it means the battery is neither charging nor discharging. When the ammeter goes low, it means the battery is dischaging. If the ammeter stays low, it's possible the alternator is crapping out. as for the battery light... I dunno about that one. With the vehicle shut off, check the voltage on the battery with a multimeter. It should read over 12 volts. Then start the truck, with ALL accessories turned off, and read the voltage again. It should be at around 13v (sometimes I see as high as ~14 on mine). if voltage is low with truck running and accessories off, get the alternator tested. __________________ Daily Driver: 1997 V8 Explorer - K&N FIPK, Granatelli MAF, 3" Body Lift, WAR-153 Shackles, Torsion Twist, custom-built skidplate. 4.56s, Ion Alloy 133's, 33x12.5 Interco TrXus STS. 1986 Bronco2: RIP

10-05-2008, 05:43 PM	#4
Blee1099 Evil Asian Elkridge, MD 91 Join Date: Mar 2002 Posts: 14,327 Vehicle Specs	I would suspect the alternator? Does the tach bounce or any of the other gauges? I would take it to Advance auto or similar place and have the alternator tested. Grab a multimeter (digital one if you have one) and place it on the battery and start the engine and have someone keep the rpm's at about 1500-2000 constantly. See if the voltage drops below 13.8. Another thing you can do is start the truck and pull the negative terminal. If the truck dies, then your alternator is shot. __________________ Decals & Stickers EF Shirts EF Pullover Hoodies EF Zip Up Hoodies EF Travel Coffee Mugs Buy Any 2 and get 2nd half off Bottoms Up Rock Racing

10-05-2008, 06:02 PM	#5
gavin Elite Explorer Anchorage, Alaska '97 Explorer XLT AWD 5.0L Join Date: Sep 2002 Posts: 3,047 Vehicle Specs	maybe the battery light means voltage is low? and the ammeter would read low if the battery was discharging for whatever reason (ie, the alternator isn't providing enough juice to keep the battery charged and run the vehicle). I would still HIGHLY recommend, first thing you do, is check the voltage, as I mentioned in my first post. First check the voltage between the battery posts, with the engine NOT running. It should read around 12.5 or so. Now, start the truck, leaving ALL accessories turned off. At idle, the reading should be over 13... 13.5'ish is where it most likely goes. My guess, is that the battery light comes on, because the battery is below a set voltage threshold. It stays on, because the alternator isn't providing enough juice, or because the voltage regulator is toast and isn't providing the correct voltage. Either way, it would be the alternator. __________________ Daily Driver: 1997 V8 Explorer - K&N FIPK, Granatelli MAF, 3" Body Lift, WAR-153 Shackles, Torsion Twist, custom-built skidplate. 4.56s, Ion Alloy 133's, 33x12.5 Interco TrXus STS. 1986 Bronco2: RIP

10-05-2008, 09:48 PM	#7
fixxxer Wannabe Elite Explorer Aurora, Co. 93 XLT 4X4 Join Date: Sep 2006 Posts: 1,462 Vehicle Specs	The ALT light will come on if the alternator's output is too low. If your idler/tensioner is going bad, you could be merely dealing with belt slippage and that will cause your system to not charge the battery. __________________ -Larry 93 XLT 4x4 90 Celica GTS 97 Camry Ford Explorer and Ranger Owner's Guides and more...

10-05-2008, 05:28 PM	#3
Steeda90GT Wannabe Elite Explorer Central NJ 99 Sport Join Date: Jul 2006 Posts: 448 Vehicle Specs (Original Poster)	Pardon my lingo, I'm a Software Developer, not a mechanic so I just kind of make things up along the way. So what is the purpose of the battery light on the cluster? Does it come on when the volts are low and the alternator isn't charging properly? I also noticed the belt tensioner looked bad. The entire assembly appears to be loose..and when the truck is running, it wobbles.

10-05-2008, 09:29 PM	#6
TheJackal Wannabe Elite Explorer Mandeville, LA 1999 Explorer XL 2WD Join Date: Aug 2007 Posts: 1,067 Vehicle Specs	The charging indicator ("battery" light) is controlled by the regulator. If the light is on, it means, as stated before, your battery isn't being charged. Take care of this ASAP, to avoid being stranded with a dead battery.

10-05-2008, 09:52 PM	#8
corkey Elite Canuck, Eh ?? In the Great White North where winter never seems to end ,Ontario,, still ice fishing,, 96xl,99xls,old Rangers Join Date: Jan 2008 Posts: 5,448 Vehicle Specs	if the belt appears to be wobbling , and the whole thing is loose , i bet the belt is not turning the alternator enough to charge the battery properly cause the belt is slipping,, fix the loose parts first, __________________ Log Roller,, Fox Coilovers 35's and others, , Truck of the month Ranger Of Danger,,,project truck, also look for Blues Traveller Elite registry, ,

10-06-2008, 09:20 AM	#9
Steeda90GT Wannabe Elite Explorer Central NJ 99 Sport Join Date: Jul 2006 Posts: 448 Vehicle Specs (Original Poster)	Yes that's what I was thinking as well because the tensioner pulley does appear to be wobbly. I removed it and it looks like the whole unit is seperating. I'll try that first (only $40) and see if it works. If not, then new alternator. The idler pulley looks good and is spinning nicely (although the bearings are a little noisy)

10-06-2008, 09:41 AM	#11
4x4firefighter Wannabe Elite Explorer Oneonta, NY 99 Eddie Limited Join Date: May 2008 Posts: 106 Vehicle Specs	ok i got on to ask this very question. i just started having same issue. i replaced battery and instaled heavy duty altenator (all the dam lights). and it still does this! when it reads low volatage boys she is next to stalling out!!! if the vehicle is moving or u are above about 1200 RPM she is fine. its idling or stoping at a red light and everything dies down and almost stalls the car out, lights go real dim, etc......is the 1st guy have the exact same situation? __________________ 4x4firefigher.....99 Eddie Limited.... TT/ WORRIOR shackles, BLAZER off road roof lightbar http://www.myspace.com/axn6254_4x4firefighter

10-06-2008, 12:13 PM	#12
Steeda90GT Wannabe Elite Explorer Central NJ 99 Sport Join Date: Jul 2006 Posts: 448 Vehicle Specs (Original Poster)	OK, So I just came back from Vatozone and they tested my alternator. It failed. So I guess I'll pick one up. Where is everyone getting their alternators from? Vatozone has a new one for $189.99 that has a lifetime warranty. They also have a rebuilt one for $159.99 with a lifetime warranty as well. 4x4firefighter - mine just had the battery light on cluster and very low reading on the "volt meter" lol The truck still ran fine.

10-06-2008, 09:54 PM	#14
99xlsdude Wannabe Elite Explorer Southern New Jersey 1999 XLS 4.0 OHV 4X4 Join Date: Jan 2008 Posts: 53 Vehicle Specs	About a year ago, I got a rebuilt one with a lifetime replacement warranty from Pep Boys for $120.

10-07-2008, 07:52 AM	#15
Steeda90GT Wannabe Elite Explorer Central NJ 99 Sport Join Date: Jul 2006 Posts: 448 Vehicle Specs (Original Poster)	Pep Boys quoted me $170 for the lifetime warranty one. I think the alternators are different between the SOHC and OHV, right?

10-07-2008, 07:53 AM	#16
Steeda90GT Wannabe Elite Explorer Central NJ 99 Sport Join Date: Jul 2006 Posts: 448 Vehicle Specs (Original Poster)	BTW - the $75 eBay ones are damn tempting..

10-11-2008, 07:45 PM	#19
Steeda90GT Wannabe Elite Explorer Central NJ 99 Sport Join Date: Jul 2006 Posts: 448 Vehicle Specs (Original Poster)	UPDATE: OK - I decided to buy a reman unit (lifetime replacement) for $129.99. I also installed a new belt and a tensioner (the original one was starting to split. Everything is great, no more battery light on cluster and my "volt gauge" isn't reading low anymore!

10-13-2008, 09:52 AM	#20
kgbrgv Wannabe Elite Explorer Los Fresnos, Texas 1993 Ranger Join Date: Oct 2008 Posts: 3 Vehicle Specs	I have a similar problem. I have installed new battery and alternator. The volt meter is low and warning light is on. What next.