Notices
1999 - 2003 7.3L Power Stroke Diesel  
Sponsored by:
Sponsored by: DP Tuner

Battery light flickering

Thread Tools
 
Search this Thread
 
Old Sep 22, 2012 | 07:40 PM
  #1  
cutlass's Avatar
cutlass
Thread Starter
|
Elder User
Joined: Feb 2010
Posts: 721
Likes: 1
Battery light flickering

I know- another flickering battery light thread. Well, my battery light flickers at idle and when I increase the RPM's, the battery light stays on steady.

Alternator or voltage regulator?

Since I started writing this thread, I decided I needed the voltage at the batteries while the truck was running and the battery light was on constantly no matter what RPM I was running it at. I checked battery voltage when the truck was not running and it read 12.6 volts for each battery. While running they read 12.4 volts.

What does everyone think?
 
Reply
Old Sep 22, 2012 | 07:53 PM
  #2  
indyF-350psd's Avatar
indyF-350psd
you can't fix stupid!
Joined: Mar 2008
Posts: 1,906
Likes: 2
Club FTE Silver Member

alternator......with increased rpm its putting out more juice so the light quits.......time for a new one....
 
Reply
Old Sep 22, 2012 | 08:02 PM
  #3  
big poppa's Avatar
big poppa
Post Fiend
Joined: Feb 2008
Posts: 10,977
Likes: 5
From: Lancaster, Pa.
I say a reputable rebuild, alt..
 
Reply
Old Sep 22, 2012 | 08:32 PM
  #4  
roostercrows's Avatar
roostercrows
Laughing Gas
Joined: Aug 2005
Posts: 831
Likes: 0
From: Port Elgin, On
I agree with the first 2 posts, the same thing happened to me.
 
Reply
Old Sep 22, 2012 | 08:54 PM
  #5  
BadDogKuzz's Avatar
BadDogKuzz
Postmaster
Joined: Dec 2010
Posts: 2,951
Likes: 4
From: Gary,Indiana
I concur with all the above. But I would start by taking the alt. off and going to a parts store and have them bench test it. Also I would stay away from the remans done in Mexico or China.
 
Reply
Old Sep 22, 2012 | 09:40 PM
  #6  
cutlass's Avatar
cutlass
Thread Starter
|
Elder User
Joined: Feb 2010
Posts: 721
Likes: 1
As I've had a little time to think about why it quit on me, I remember when I was trying to start my new engine for the first time, I was not able to start it after many cranks. A short while later I realized my DP tuner was not pushed all the way into the CPM.

Since all that cranking drained the battery, I hooked up a charger and a buddy suggested I switch the starter over to START mode. I told him I thought that wouldn't be good for the electronics in the truck but he reassured me it wouldn't harm a thing. So I tried to start the truck with the charger on START mode at 75 amps.

Could that have fried my alternator?
 
Reply
Old Sep 22, 2012 | 09:43 PM
  #7  
cutlass's Avatar
cutlass
Thread Starter
|
Elder User
Joined: Feb 2010
Posts: 721
Likes: 1
Originally Posted by indyF-350psd
alternator......with increased rpm its putting out more juice so the light quits.......time for a new one....

The battery light was actually constantly on when I was at higher RPM's and dropped back down to a flicker at idle.

Now, the light is on no matter what RPM it's running at.
 
Reply
Old Sep 22, 2012 | 10:27 PM
  #8  
landmobile's Avatar
landmobile
Senior User
Joined: Mar 2012
Posts: 492
Likes: 0
From: Jenkintown, PA
12.4V running = bad alternator. I agree that a good local shop is the best place for a rebuild.

I don't think cranking the engine with the charger connected damaged the alternator. Most battery chargers can't supply enough current to start a 7.3 on their own. When the engine is cranked, the voltage just drops too low to fire the injectors or turn the starter motor. The only electronics problems I have seen were from using a 24V battery charger/engine starter on a 12V vehicle.

Chris
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Top 10 Ford Truck Tragedies

 Joe Kucinski
story-1

AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

 Brett Foote
story-2

Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

 Michael S. Palmer
story-3

Ford's 2001 Explorer Sportsman Concept Looks For a New Home

 Verdad Gallardo
story-4

10 Best Ford Truck Engines We Miss the Most!

 Joe Kucinski
story-5

2026 Shelby F-150 Off-Road: Better Than a Raptor R?

 Brett Foote
story-6

2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

 Michael S. Palmer
story-7

10 Most Surprising 2026 Ford Truck Features!

 Joe Kucinski
story-8

Top 10 Ford Trucks Coming to Mecum Indy 2026

 Brett Foote
story-9

5 Best / 5 Worst Ford Truck Wheels of All Time

 Joe Kucinski
Old Sep 22, 2012 | 10:33 PM
  #9  
1fixitman's Avatar
1fixitman
Laughing Gas
Joined: Aug 2012
Posts: 915
Likes: 3
From: Palatka, FL
HOW MANY MILES ON YOUR TRUCK?
It is possible that your brushes in your alternator are about to fail and near the springs. It could also have bad bearings and causing failure. Loosen the tension on your belt, slip the belt off and check your alternator shaft. You can not feel bad brushes but you most certainly can feel bad bearings. Check up down, left right, in out play. Have a good shop rebuild your alternator. They at least will put in new brushes and bearings. I would specify brand new bearings and ASK them how long to get the parts and get it done. Sometimes they have to order parts to get it done. I am sure they will not order parts unless they have your alternator in thier hands.
Dwayne
 
Reply
Old Sep 22, 2012 | 10:34 PM
  #10  
1fixitman's Avatar
1fixitman
Laughing Gas
Joined: Aug 2012
Posts: 915
Likes: 3
From: Palatka, FL
Also, what is your location?
 
Reply
Old Sep 22, 2012 | 10:40 PM
  #11  
cutlass's Avatar
cutlass
Thread Starter
|
Elder User
Joined: Feb 2010
Posts: 721
Likes: 1
Originally Posted by 1fixitman
Also, what is your location?

Kansas City
 
Reply
Old Sep 22, 2012 | 10:42 PM
  #12  
cutlass's Avatar
cutlass
Thread Starter
|
Elder User
Joined: Feb 2010
Posts: 721
Likes: 1
Originally Posted by 1fixitman
HOW MANY MILES ON YOUR TRUCK?
It is possible that your brushes in your alternator are about to fail and near the springs. It could also have bad bearings and causing failure. Loosen the tension on your belt, slip the belt off and check your alternator shaft. You can not feel bad brushes but you most certainly can feel bad bearings. Check up down, left right, in out play. Have a good shop rebuild your alternator. They at least will put in new brushes and bearings. I would specify brand new bearings and ASK them how long to get the parts and get it done. Sometimes they have to order parts to get it done. I am sure they will not order parts unless they have your alternator in thier hands.
Dwayne
218,000. The alternator is an aftermarket and I have no idea how long it's been on the truck.
 
Reply
Old Sep 22, 2012 | 11:06 PM
  #13  
1fixitman's Avatar
1fixitman
Laughing Gas
Joined: Aug 2012
Posts: 915
Likes: 3
From: Palatka, FL
If it is after market then just get another aftermarket and give them the core. No sense in rebuilding if it is not OEM. Check the parts websites for reviews on alternators before purchasing. I replied to the thread on soldering. I hope it all makes sense logically.
Dwayne
 
Reply
Old Sep 23, 2012 | 09:13 PM
  #14  
cutlass's Avatar
cutlass
Thread Starter
|
Elder User
Joined: Feb 2010
Posts: 721
Likes: 1
Originally Posted by 1fixitman
If it is after market then just get another aftermarket and give them the core. No sense in rebuilding if it is not OEM. Check the parts websites for reviews on alternators before purchasing. I replied to the thread on soldering. I hope it all makes sense logically.
Dwayne
Thanks Dwayne.
 
Reply
Old Sep 23, 2012 | 11:17 PM
  #15  
Stewart_H's Avatar
Stewart_H
Super Moderator
20 Year Member
Liked
Loved
Community Favorite
Joined: May 2004
Posts: 29,380
Likes: 118
From: Central Coast of CA
Club FTE Gold Member
I just replaced the alternator in my son's F350 yesterday while he was down visiting for the weekend from college.

I got him one of the O'Reilly re-manned specials with a lifetime warrantee and then gave him the volt meter I had plugged in my cigarette lighter and told him to glance at it every time he starts his engine from now on.

BTW, if I had been thinking, I'd have gotten him his own volt meter as preventive maintenance like Greg posted about way back when, in this thread: https://www.ford-trucks.com/forums/1...l#post10806422

Originally Posted by Shake-N-Bake
Last fall we added a second 7.3 to the family which became my wife's daily driver. I decided to purchase some cheap electronic volt meters that plugs into the cigarette lighter socket to monitor the battery and charging system.

What I like about these meters is that my wife doesn't have to know anything about vehicle electrical systems to know when something is wrong. I explained to her that the light should be green before she turns the key on, then it will be in the red while the glow plugs are warming, yellow when the engine starts (glow plugs still on...) and finally green again when the GPs turn off and/or the system is charged up again.
.....................
I just ordered two more, one for my rig since I gave mine to my son and one for my Lightning since it only gets driven on weekends now.

Stewart
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
rthum45
6.4L Power Stroke Diesel
1
Mar 16, 2019 11:40 AM
BEAL73
1997 - 2003 F150
13
May 15, 2018 04:05 PM
saauvenshine
1948 - 1956 F1, F100 & Larger F-Series Trucks
1
Apr 5, 2016 10:13 PM
scooterspal
1983 - 2012 Ranger & B-Series
6
Jul 18, 2014 03:17 PM
trucker41
6.0L Power Stroke Diesel
7
Dec 14, 2008 07:53 PM




All times are GMT -5. The time now is 01:59 PM.

story-0
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE
story-1
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

And it might be even better than that.

By Brett Foote | 2026-05-18 19:26:42


VIEW MORE
story-2
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Slideshow: Does lowering an F-150 Lobo RUIN the ride quality?

By Michael S. Palmer | 2026-05-18 19:20:37


VIEW MORE
story-3
Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Slideshow: Ford's bizarre fishing-themed Explorer concept has resurfaced after spending decades largely forgotten.

By Verdad Gallardo | 2026-05-12 18:07:46


VIEW MORE
story-4
10 Best Ford Truck Engines We Miss the Most!

Slideshow: The 10 best Ford truck engines we miss the most.

By Joe Kucinski | 2026-05-12 13:09:47


VIEW MORE
story-5
2026 Shelby F-150 Off-Road: Better Than a Raptor R?

Slideshow: first look at the 810 hp 2026 Shelby F-150 Off-Road!

By Brett Foote | 2026-05-12 12:50:07


VIEW MORE
story-6
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!

Slideshow: Everything You Need to Know about the 2027 Super Duty Carhartt Package!

By Michael S. Palmer | 2026-05-07 17:51:06


VIEW MORE
story-7
10 Most Surprising 2026 Ford Truck Features!

Slideshow: 10 most surprising Ford truck options/features in 2026.

By Joe Kucinski | 2026-05-05 11:17:22


VIEW MORE
story-8
Top 10 Ford Trucks Coming to Mecum Indy 2026

Slideshow: Here are the top 10 Fords coming to Mecum Indy 2026.

By Brett Foote | 2026-05-04 13:49:49


VIEW MORE
story-9
5 Best / 5 Worst Ford Truck Wheels of All Time

Slideshow: The 5 best and 5 worst Ford truck wheels of all time

By Joe Kucinski | 2026-04-29 16:49:01


VIEW MORE