Battery light illuminating
Thread Starter
|
Senior User
Joined: Sep 2013
Posts: 157
Likes: 0
From: Tampa, Florida
Battery light illuminating
The battery light upon start up doesn't illuminate, then at random times it illuminates solid for a few minutes then goes off, for a few minutes. I hooked up the gauge and the voltage fluctuates from 11.4 volts to 13.5 volts...the light comes on around 12 volts from what I can tell.
I am going to take the batteries in tomorrow to be tested, I just purchased this truck from a GMC dealership 2 months ago, and they changed out one of the batteries because it was bad.. I'm sure I will need to replace both batteries, should I take the alternator off and have that tested too? Can the auto parts place test the batteries on the vehicle or do I need to take those out too? Thanks.
Sent from my DROID BIONIC using IB AutoGroup
I am going to take the batteries in tomorrow to be tested, I just purchased this truck from a GMC dealership 2 months ago, and they changed out one of the batteries because it was bad.. I'm sure I will need to replace both batteries, should I take the alternator off and have that tested too? Can the auto parts place test the batteries on the vehicle or do I need to take those out too? Thanks.
Sent from my DROID BIONIC using IB AutoGroup
Lead Driver
Joined: Feb 2011
Posts: 8,241
Likes: 155
From: L.A. (Lower Alabama)
As you verified with the voltage readings, the battery light is pretty much right. As always verify battery connections are clean and tight, including cables from the engine block to the frame. There's one on each side on my '06.
The connector plug on the back of the alternator is prone to overheating. Look for the plastic part to be brittle and corrosion in the connector.
Batteries can be load tested in the truck but one of cables (doesn't matter which one) should be disconnected. Batteries are wired in parallel and a good battery will "cover up" for a bad one if everything is connected during testing.
Alternator issues are often intermittent and more frequent as it heats up. A bench test should include a good load and it may take a few minutes to show up. The alternator is likely your problem and hopefully it hasn't taken a battery out with it. Also, low voltage is hard on the power side of the FICM. Try not to drive it much until repairs can be done.
The factory charging system (single alternator) is borderline as far as amperage output. If the budget allows there are several options for a higher amp alternator, from higher rated factory units to aftermarket. Many threads here at FTE with details on the options.
The connector plug on the back of the alternator is prone to overheating. Look for the plastic part to be brittle and corrosion in the connector.
Batteries can be load tested in the truck but one of cables (doesn't matter which one) should be disconnected. Batteries are wired in parallel and a good battery will "cover up" for a bad one if everything is connected during testing.
Alternator issues are often intermittent and more frequent as it heats up. A bench test should include a good load and it may take a few minutes to show up. The alternator is likely your problem and hopefully it hasn't taken a battery out with it. Also, low voltage is hard on the power side of the FICM. Try not to drive it much until repairs can be done.
The factory charging system (single alternator) is borderline as far as amperage output. If the budget allows there are several options for a higher amp alternator, from higher rated factory units to aftermarket. Many threads here at FTE with details on the options.
Mountain Pass
Joined: Nov 2005
Posts: 164
Likes: 2
From: Cloverdale VA
I had the same issue. I questioned it foolishly and ended up needing batteries, an alternator and had to re-solder my FICM because it ran too long with low voltage. So don't delay just because the light isn't on constantly.
Thread Starter
|
Senior User
Joined: Sep 2013
Posts: 157
Likes: 0
From: Tampa, Florida
The HO alternators are around $170 on Ebay, that's 250 amp right?
http://www.ebay.com/itm/251140362113...84.m1438.l2649
http://www.ebay.com/itm/251140362113...84.m1438.l2649
Certified Thread Hijacker
Joined: Aug 2001
Posts: 14,441
Likes: 60
The HO alternators are around $170 on Ebay, that's 250 amp right?
250Amp High Output Alternator Ford E F Series E450 F450 Excursion 6 0L 2003 2007 | eBay
250Amp High Output Alternator Ford E F Series E450 F450 Excursion 6 0L 2003 2007 | eBay
A good deal is step-up to the 140 amp 6G commonly used in the dual alternator and snow plow equipped 6.0 trucks, along with a 58mm pulley. Or a 130 amp 3G alternator from a 94-97 7.3 truck. That option needs a conversion pigtail or hardwired.
Josh
Trending Topics
Hotshot
Joined: Dec 2003
Posts: 15,369
Likes: 121
From: Stuttgart, Ar
The HO alternators are around $170 on Ebay, that's 250 amp right?
250Amp High Output Alternator Ford E F Series E450 F450 Excursion 6 0L 2003 2007 | eBay
250Amp High Output Alternator Ford E F Series E450 F450 Excursion 6 0L 2003 2007 | eBay
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
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
Thread Starter
|
Senior User
Joined: Sep 2013
Posts: 157
Likes: 0
From: Tampa, Florida
Sent from my DROID BIONIC using IB AutoGroup
Thread
Thread Starter
Forum
Replies
Last Post