Battery Light Flashing
Thread Starter
|
New User
Joined: Nov 2012
Posts: 4
Likes: 0
Battery Light Flashing
Hi All,
The Battery Light flashes on 2002 excursion 7.3l. I have been having a problem for several months, one of the batteries ended up being shot, alternator checks out. Problem is there is nor rhyme or reason as to when or if the light will flash, it is not consistent with a shorted wire that is bouncing around and grounding out. If anyone has any ideas, I would greatly appreciate them. Thanks, Paul
The Battery Light flashes on 2002 excursion 7.3l. I have been having a problem for several months, one of the batteries ended up being shot, alternator checks out. Problem is there is nor rhyme or reason as to when or if the light will flash, it is not consistent with a shorted wire that is bouncing around and grounding out. If anyone has any ideas, I would greatly appreciate them. Thanks, Paul
Elder User
Joined: Jan 2012
Posts: 777
Likes: 2
Mine was doing that too (V10 though). It was the alternator. Seems like it would charge then stop then charge then stop, etc.
Got a junkyard one off an F250 about 3 months/5k miles ago and haven't seen the light flash or had charging problems since.
Got a junkyard one off an F250 about 3 months/5k miles ago and haven't seen the light flash or had charging problems since.
Super Moderator
Joined: May 2004
Posts: 29,380
Likes: 118
From: Central Coast of CA
Hi All,
The Battery Light flashes on 2002 excursion 7.3l. I have been having a problem for several months, one of the batteries ended up being shot, alternator checks out. Problem is there is nor rhyme or reason as to when or if the light will flash, it is not consistent with a shorted wire that is bouncing around and grounding out. If anyone has any ideas, I would greatly appreciate them. Thanks, Paul
The Battery Light flashes on 2002 excursion 7.3l. I have been having a problem for several months, one of the batteries ended up being shot, alternator checks out. Problem is there is nor rhyme or reason as to when or if the light will flash, it is not consistent with a shorted wire that is bouncing around and grounding out. If anyone has any ideas, I would greatly appreciate them. Thanks, Paul
When you discovered the one battery being shot, you replaced them both, correct?
Never ever replace just one battery.
Stewart
Super Moderator
Joined: May 2004
Posts: 29,380
Likes: 118
From: Central Coast of CA
I have one of these in every vehicle I own.
I bought one for each vehicle because of Greg's thread found here: https://www.ford-trucks.com/forums/1...l#post10806422
Greg's follow-up thread: https://www.ford-trucks.com/forums/1...l#post11679030
Absolutely invaluable for helping catch a problem before it becomes a problem.
Stewart
I bought one for each vehicle because of Greg's thread found here: https://www.ford-trucks.com/forums/1...l#post10806422
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.
So, last Friday she told me that the engine seems to be cranking slower and it's been taking a lot longer for the meter to go back to green once the engine is started. I checked it out on Sunday and sure enough, the meter was yellow and then showed only 10.5 volts with key on. Amazingly the engine started but it sure was slow to crank so I had the batteries load tested and one was bad and the other was weak. The date code on her batteries was May of 2006 so they lasted for a good while. The brand was one that I've never heard of before (Centennial)?
At any rate, a new pair of Interstate batteries from Costco and everything is good for a few more years.
I am glad I had the meter and my wife was attentive enough to notice something was wrong because it was only a matter of time before she would have been stranded somewhere needing a jump start. From time to time I travel so with my luck it would have happened while I was out of town to boot....
Here are some photos of the meter that I use and what the readings are during the various conditions. If I remember correctly, these photos were taken during a cold start with ambient temps around 30-40 degrees.
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.
So, last Friday she told me that the engine seems to be cranking slower and it's been taking a lot longer for the meter to go back to green once the engine is started. I checked it out on Sunday and sure enough, the meter was yellow and then showed only 10.5 volts with key on. Amazingly the engine started but it sure was slow to crank so I had the batteries load tested and one was bad and the other was weak. The date code on her batteries was May of 2006 so they lasted for a good while. The brand was one that I've never heard of before (Centennial)?
At any rate, a new pair of Interstate batteries from Costco and everything is good for a few more years.
I am glad I had the meter and my wife was attentive enough to notice something was wrong because it was only a matter of time before she would have been stranded somewhere needing a jump start. From time to time I travel so with my luck it would have happened while I was out of town to boot....Here are some photos of the meter that I use and what the readings are during the various conditions. If I remember correctly, these photos were taken during a cold start with ambient temps around 30-40 degrees.
Absolutely invaluable for helping catch a problem before it becomes a problem.
Stewart
Last edited by Stewart_H; Dec 31, 2012 at 04:20 PM.
Post Fiend
Joined: Mar 2007
Posts: 26,966
Likes: 50
From: Texas
Where did you get your alternator? I used to go through about one alternator a year from autozoo. I've got a plug in volt meter similar to what Stewart shows that I can use.
I'd guess that regardless of what they are telling you when it's tested, the alternator is why your light is flashing and it's time to replace it before it kills the new batteries.
I'm currently trying out a 140 amp alternator that was available for the 6.0 and has a larger case to it. It's still new to me so no longevity reports yet, but I'm hoping it does better than the "lifetime" 110 amp alternators I've been using.
I'd guess that regardless of what they are telling you when it's tested, the alternator is why your light is flashing and it's time to replace it before it kills the new batteries.
I'm currently trying out a 140 amp alternator that was available for the 6.0 and has a larger case to it. It's still new to me so no longevity reports yet, but I'm hoping it does better than the "lifetime" 110 amp alternators I've been using.
Trending Topics
Super Moderator
Joined: May 2004
Posts: 29,380
Likes: 118
From: Central Coast of CA
Make sure all your grounds have good clean contact too.
Glad to hear you replaced both batteries!
Chris, I am hoping that 140 alt works well. When it comes time to replace mine, I plan on going the same route you have since you've blazed the path!
Stewart
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Freshman User
Joined: Oct 2007
Posts: 42
Likes: 0
I am having the same battery light issue. I have a 2000 7.3 in my Excursion. Battery are interstate less than a year old. Volt meter says each battery is at 11.5 volts. The post at the rear of the alternator shows 11.5 volts when running. This alternator is 2 years old.
I am guessing alternator but want to check here before I drop cash on a new one. Post up fellas.
I am guessing alternator but want to check here before I drop cash on a new one. Post up fellas.
Post Fiend
Joined: Mar 2007
Posts: 26,966
Likes: 50
From: Texas
I am having the same battery light issue. I have a 2000 7.3 in my Excursion. Battery are interstate less than a year old. Volt meter says each battery is at 11.5 volts. The post at the rear of the alternator shows 11.5 volts when running. This alternator is 2 years old.
I am guessing alternator but want to check here before I drop cash on a new one. Post up fellas.
I am guessing alternator but want to check here before I drop cash on a new one. Post up fellas.
Freshman User
Joined: Oct 2007
Posts: 42
Likes: 0
It had been running for a while before I checked it and it was at 11.5 volts from the alternator.
have a code thrown for the #8 glow plug. Would my procrastination in fixing that be a cause for the alternator low voltage?
have a code thrown for the #8 glow plug. Would my procrastination in fixing that be a cause for the alternator low voltage?
Elder User
Joined: Jan 2012
Posts: 777
Likes: 2
11.5 volts isn't normal for either the batteries or from the alternator. The batteries (if I'm not mistaken) should read 12.4v with the truck off and 13v+ with the truck running, no? You're probably draining the living crap out of your batteries and slowly killing them since the alternator isn't charging them the way it should.
Thread Starter
|
New User
Joined: Nov 2012
Posts: 4
Likes: 0
I will have the alternator checked again. I bought it from Check er, but had it tested at a separate auto shop. The problem with testing it when under a load is that it normally only comes on when driving. I did manage to get it to come on in park, but that was revving to about 3,000 rpm.