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Replaced alternator, but battery light stays on
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E. Long  Club OwnerSuperMotors Owner
Subscriber
Subscriber since 1/1/2001
• Atlanta, GA, USA
• Registered on 1/23/2001
• 2,228 posts
1 Vehicle
Posted:9/29/2005 22:03
My alternator went bad earlier this week. I had been experiencing a weak start here and there over the weekend and the battery light finally came on Monday on the way home from the office. I tested the batteries with my voltmeter and at the time they were at about 11.85 volts each with the vehicle turned off. I then started the vehicle and tested the alternator, it was only putting out about 11.8 volts. I had all accessories turned off.

I replaced the alternator tonight, jumped the X with the Galaxie (batteries were too low to get the diesel running), and tested the alternator. It read 14.2. At the batteries, they read 13.99 with the X running without any accessories on. Tested the batteries with the X off after charging -- in the 12.2 range.

It starts fine again, runs fine again, no electrical weirdness anymore, but the battery light still stays on. Anyone know why this might be? What else does the battery light "detect?"

-Eric

'67 Galaxie 500 - 390 FE, .030" over, FE to AOD adapter, disc brake conversion. The Daily Driver.
'00 Excursion - 7.3L PSD, LANDYOT Gen-II Radius Rods, Factory Tech Valve Body, 200K+ miles and going
kiarasue
• Enumclaw, WA, USA
• Registered on 9/27/2005
• 81 posts
Posted:9/30/2005 00:58
Hi, I had this problem in my 64 sport coupe. It was a generator then but when I was reading up on the system I learned that to keep the light off, you have to have power from both sides of that indicator light. See if the alt. goes out that side becomes ground and the bulb lights and as you can see, when you turn the key on the indicator is lit till the engine starts. I'm bidding on a Haynes manual today so I can have some diagrams to look at and more importantly know what color they are. Bill
Eddie Henson
• Cordova, TN, USA
• Registered on 12/8/2004
• 122 posts
1 Vehicle
Posted:9/30/2005 02:24
Hi Eric,

My wife's car had this problem a few years ago. With the car running, the battery light would stay on very dimly. After confirming that the alternator was bad and replacing it, the light still stayed on, very dimly, although the voltage at the batt. with the vehicle running showed it was getting a charge. After shutting down and checking the voltage again it was at a solid 12 volts. To make a long story short, I ended up replacing the battery also and the light went out. I guess the short perid of time the car ran with the weak alternator drained enough of the battery that it would never get a good, full charge and the light never went out. I also remember reading on the net a while back that in order to get a good charge on the batts. after starting up, you need to drive around for roughly 10-15 minutes, fwiw. Hope this helps.



Eddie Henson
2000 Ford Excursion XLT 7.3L PSD
203 degree Thermo; Factory Tech valve body; CCV mod; HX mod; Rancho RS9000 shocks; Shimmed FPR @ 67; Walker BTM; Evans NPG Coolant; Dieselsite Coolant Filter Kit; Dieselsite Heater Shutoff Valve; Zoodad Mod; WeatherTech In-channel Visors; Acetoned Badges; PSD Badges; Landyot's Gen II Radius Rods
"If you don't like America, Get the hell out !!" - John Rich
edited 9/30/2005 02:27
E. Long  Club OwnerSuperMotors Owner
Subscriber
Subscriber since 1/1/2001
• Atlanta, GA, USA
• Registered on 1/23/2001
• 2,228 posts
1 Vehicle
Posted:9/30/2005 07:55
I'll put a couple hundred miles on it today, hopefully it will fix itself. I'd rather purchase 2 new batteries when they are really needed. Although, after 5 years and nearly 156,000 miles, I can't complain that these 2 have lasted this long.

-Eric

'67 Galaxie 500 - 390 FE, .030" over, FE to AOD adapter, disc brake conversion. The Daily Driver.
'00 Excursion - 7.3L PSD, LANDYOT Gen-II Radius Rods, Factory Tech Valve Body, 200K+ miles and going
Eddie Henson
• Cordova, TN, USA
• Registered on 12/8/2004
• 122 posts
1 Vehicle
Posted:9/30/2005 13:53
I think after 5 years you have reached the life limit on the batteries.I replaced mine earlier this summer after I started noticing the engine seemed to have a difficult time starting up. I had know way of telling how long the others had been installed since I'm not the original owner on my X. Plus with you living in yankee territory you might want to replace them before the cold weather sets in and leaves you stranded.

Eddie Henson
2000 Ford Excursion XLT 7.3L PSD
203 degree Thermo; Factory Tech valve body; CCV mod; HX mod; Rancho RS9000 shocks; Shimmed FPR @ 67; Walker BTM; Evans NPG Coolant; Dieselsite Coolant Filter Kit; Dieselsite Heater Shutoff Valve; Zoodad Mod; WeatherTech In-channel Visors; Acetoned Badges; PSD Badges; Landyot's Gen II Radius Rods
"If you don't like America, Get the hell out !!" - John Rich
Scott Stover
• Fayetteville, NC, USA
• Registered on 4/16/2004
• 354 posts
1 Vehicle
Posted:9/30/2005 16:40
Ive gotta replace mine here before the cold sets in, mine is an Autozone battery and its started to seep out of the top around the servicing caps, so Im figurein its about time for a change.

Scott
2000 X 4x4 V-10 4.3 LS
K&N
Gibson Catback
"Custom" Kickplates
E. Long  Club OwnerSuperMotors Owner
Subscriber
Subscriber since 1/1/2001
• Atlanta, GA, USA
• Registered on 1/23/2001
• 2,228 posts
1 Vehicle
Posted:10/1/2005 13:56
Battery light still has not gone off. The X continues to start like a champ though -- no sign of weak batteries at all.

-Eric

'67 Galaxie 500 - 390 FE, .030" over, FE to AOD adapter, disc brake conversion. The Daily Driver.
'00 Excursion - 7.3L PSD, LANDYOT Gen-II Radius Rods, Factory Tech Valve Body, 200K+ miles and going
E. Long  Club OwnerSuperMotors Owner
Subscriber
Subscriber since 1/1/2001
• Atlanta, GA, USA
• Registered on 1/23/2001
• 2,228 posts
1 Vehicle
Posted:10/1/2005 17:32
More updates:

- Reseated all fuses, just to be sure
- Checked the battery and alternator-related fuses under the hood -- they are OK
- Unhooked both batteries
- Cleaned battery posts and positive/negative terminals
- Checked the 2-wire plug on the back of the alternator while the truck was running, it read 13.9-14.2v on the red wire (after the initital start), 1.5v (or so) on the green wire
- Batteries read 12.8 volts each when the vehicle is not running
- Batteries read 13.9-14.2 volts while vehicle is running

I'm at a loss for what the problem would be.

-Eric

'67 Galaxie 500 - 390 FE, .030" over, FE to AOD adapter, disc brake conversion. The Daily Driver.
'00 Excursion - 7.3L PSD, LANDYOT Gen-II Radius Rods, Factory Tech Valve Body, 200K+ miles and going
edited 10/1/2005 17:33
E. Long  Club OwnerSuperMotors Owner
Subscriber
Subscriber since 1/1/2001
• Atlanta, GA, USA
• Registered on 1/23/2001
• 2,228 posts
1 Vehicle
Posted:10/10/2005 18:38
While the batteries tested fine earlier this month when the temps were considerably warmer, now that it's dipping down in the 30's and 40's overnight, the X is having a problem starting in the mornings.

I ordered two Optima Yellow Top D34's and will be replacing my stock batteries. Hopefully the battery light goes off after this upgrade.

-Eric

'67 Galaxie 500 - 390 FE, .030" over, FE to AOD adapter, disc brake conversion. The Daily Driver.
'00 Excursion - 7.3L PSD, LANDYOT Gen-II Radius Rods, Factory Tech Valve Body, 200K+ miles and going
dieseldave
• Montrose, CO, USA
• Registered on 10/14/2005
• 4 posts
Posted:10/14/2005 23:43
E.:

Have you tried clearing the codes on the OBD II? Not sure if that will eliminate your problem, but I'm in the midst of exactly the same situation - still waiting on the alternator to arrive tomorrow, and I've got two relatively new EverStart Extreme 1000 CCA batteries that may have to be replaced, as they are not taking more than about 65% charge each after running back from Telluride to Montrose last night. Arrived home after the Ex had shut down all non-essential systems (stereo, ABS, airbags, instruments.....) with only head- and running lights operating. Output voltage was ~10V, and the batteries were down to about 10% and 24%, respectively, so they suffered a pretty severe drain.

I'm planning to have to clear whatever codes were generated during this event, and I have an OBD II reader/eraser with which to do it. I'll let you know how I make out after all is said and done!

D.
Ford Excursion Forums > Ford Excursion V8, V10, and Powerstroke > Excursion Discussion
Replaced alternator, but battery light stays on
Thread Statistics:     Users to Post: 10   |   Total Posts: 27   |   Total Views: 11929
You must be logged in to post in or subscribe to this thread.Pages: 1 2 3

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