Battery Light
Thread Starter
|
More Turbo
Joined: Mar 2016
Posts: 644
Likes: 10
Battery Light
Running down the road today and the battery light came on. Went on and off intermittently as I drive home and the tuner showed 11.5v. Got home, shut it off (didn't mean to) and restarted it. Tested voltage at the batteries and was over 14. Ideas? Need to take it for a drive and see if it repeats.
Lead Driver
Joined: Jul 2004
Posts: 6,951
Likes: 512
From: Foothills, CA
Just saw a post from, Jack I think? Who called the light: not so much as a battery light as an alternator (warning) light. Might want to get the Alt tested, check connections and grounds, etc...
Postmaster
Joined: Sep 2010
Posts: 3,472
Likes: 2
From: Southern Cal
The light that comes on is specifically related to the alternator. When it comes on, The alternator isn't charging. Nothing to do with the batteries.
Running at 11.5v isn't good for your ficm so I wouldn't drive much.
Your batteries might still be close to a full charge if you haven't driven too far, but somethings wrong, showing 14v. Expect to see your batteries at 12.6-12.8 volts if fully charged when static.
If the alt light is only, check your 3 fittings on the back of the alternator first. If all is clean and secure, chances are the alternator is bad.
Keep in mind, the internal regulator might be bad but it's just easier to replace the complete alternator.
Have you jumped someone recently? The diodes that convert ac current to DC can blow out when trying to jump another vehicle, especially if your vehicle was running.
Running at 11.5v isn't good for your ficm so I wouldn't drive much.
Your batteries might still be close to a full charge if you haven't driven too far, but somethings wrong, showing 14v. Expect to see your batteries at 12.6-12.8 volts if fully charged when static.
If the alt light is only, check your 3 fittings on the back of the alternator first. If all is clean and secure, chances are the alternator is bad.
Keep in mind, the internal regulator might be bad but it's just easier to replace the complete alternator.
Have you jumped someone recently? The diodes that convert ac current to DC can blow out when trying to jump another vehicle, especially if your vehicle was running.
Thread Starter
|
More Turbo
Joined: Mar 2016
Posts: 644
Likes: 10
I don't think I have that problem. After I restarted the truck the first time all was normal and the voltage was reading normal at 14v. Went to check it again and battery light is on again and meter is reading 11.5. Pretty sure the alternator is fried, just figuring which is best to replace it.
Trending Topics
Cargo Master
Joined: Aug 2012
Posts: 2,872
Likes: 951
From: Kaufman TX
I don't think I have that problem. After I restarted the truck the first time all was normal and the voltage was reading normal at 14v. Went to check it again and battery light is on again and meter is reading 11.5. Pretty sure the alternator is fried, just figuring which is best to replace it.
However keeping volts as high as possible is good for the life of the FICM and it seems the 110's run at 13.5-13.8 more often than not. For that reason I chose to go with a less available higher output unit.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Fleet Mechanic
Joined: Aug 2012
Posts: 1,760
Likes: 21
Unless you have duel alts. then the one your replacing is a 110amp. so a 135amp is an upgrade. Either one will work.
Postmaster
Joined: Sep 2010
Posts: 3,472
Likes: 2
From: Southern Cal
I'd upgrade your "heavy duty" stock 110 amp alternator to the 135 amp, knowing you're charging two batteries and if towing, the tow vehicle battery as well.
Get the forever warranty if buying at OReilly's.
They can go bad sooner then expected.
Get the forever warranty if buying at OReilly's.
They can go bad sooner then expected.
Lead Driver
Joined: Jul 2004
Posts: 6,951
Likes: 512
From: Foothills, CA
When we ordered our '07 there were two options over the stock 110A: a HD 140A (which I think was included with the snowplow prep package) and then the duals, with a 110 below and a 140 on top.
I think the 140 with an overdrive pulley is good, and being able to get it replaced easily is important, but it might not be enough for really cold climates and/or if you have a lot of electrical consumers (big stereo, charging trailers, etc.).
One of the biggest improvements I saw was upgrading some of the cabling from the Alt to Pass battery and between batts. Take a look at this thread:
https://www.ford-trucks.com/forums/1...tery-life.html
I think the 140 with an overdrive pulley is good, and being able to get it replaced easily is important, but it might not be enough for really cold climates and/or if you have a lot of electrical consumers (big stereo, charging trailers, etc.).
One of the biggest improvements I saw was upgrading some of the cabling from the Alt to Pass battery and between batts. Take a look at this thread:
https://www.ford-trucks.com/forums/1...tery-life.html