Charging system
Thread Starter
|
New User
Joined: Mar 2019
Posts: 10
Likes: 0
Charging system
Hi guys, I am Ed. I have a 2003 Expedition. I love it. My problem is either battery or alternator. I check the voltage with the engine off and I get around 11.5 volts on the terminals. I start the engine and the voltage is still 11.5 volts. I get a battery light. At 2k RPM, the light goes off. After it idles for a couple of minutes, the battery light comes back on. I am in the soup either way. But can anyone suggest a way for a novice to tell the problem? Thanks
ed77
ed77
Fleet Owner
Joined: Aug 2010
Posts: 21,253
Likes: 1,656
From: Reynoldsburg, Ohio
Your problem could be both failing components but almost 100% your alternator is on its way out, quickly at that. Every symptom you post points to it.
The fact you get nothing more than battery voltage at the terminals with engine running shows the alternator has no output. Since you don't idle at 2K RPM that's not a reliable test, that the battery warning light comes on after a while just points more and more towards the alternator.
You'll want to address this ASAP before you ruin the battery too. If you replace the alternator make sure every every connection and terminal is completely free of corrosion. I usually replace the serpentine belt too especially if hasn't been changed recently.
The fact you get nothing more than battery voltage at the terminals with engine running shows the alternator has no output. Since you don't idle at 2K RPM that's not a reliable test, that the battery warning light comes on after a while just points more and more towards the alternator.
You'll want to address this ASAP before you ruin the battery too. If you replace the alternator make sure every every connection and terminal is completely free of corrosion. I usually replace the serpentine belt too especially if hasn't been changed recently.
Thread Starter
|
New User
Joined: Mar 2019
Posts: 10
Likes: 0
I visited one of the major stores and had two tests. One on vehicle conclusion was definitely the alternator. Later in the day, I had the battery tested in the same shop for an hour. Conclusion, battery bad. That baffled me. So after 165,000 miles, I have decided to probably replace both. Thank you guys for your help and suggestions.
Fleet Owner
Joined: Apr 2008
Posts: 24,322
Likes: 5,132
From: 0,0,1
Just an FYI. On my 01 Navigator the battery light would be on at idle then go out as the RPMs increased. I bought a new set of brushes and took the alternator apart. I replaced the brushes and cleaned the armature contacts. After putting it all back together the alternator worked perfect and has to this day. The repair cost me about $15 for the brushes when a new alternator was up around $300.
Trending Topics
Thread Starter
|
New User
Joined: Mar 2019
Posts: 10
Likes: 0
Sounds like you had the same problem as I do. I, however, must opt for another alternator. I would not know a brush from a boomerang.Found a used one for $70. Not ideal, but gotta tie some ends up. Few months, and I will replace it. Thanks for your help and suggestion(s).
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
Thread Starter
|
New User
Joined: Mar 2019
Posts: 10
Likes: 0
Thank you. I checked the voltage on the battery engine off and got 12.2 V Engine running, I get 11.5 V and a voltage light. I drove, fearfully, about 10 miles and checked again. The voltages had not changed. New battery. Replaced alternator. I am puzzled.
More Turbo
Joined: Apr 2014
Posts: 660
Likes: 7
From: Central NJ
If you have a new battery the voltage should be around 12.6 or better. Your problem is going to be wiring (that includes cleaning the battery terminals). Again, just because a part is new, doesn't necessarily make it good.
Thread Starter
|
New User
Joined: Mar 2019
Posts: 10
Likes: 0
The battery connectors are pretty crappy. But it ain't like it was back in the day. Red to positive black to black. There are at least three connectors at the positive post. But you are right. Gotta clean up those connectors. Will post what happens. Thanks
Fleet Owner
Joined: Apr 2008
Posts: 24,322
Likes: 5,132
From: 0,0,1
Is the belt tight? If not there could be an issue with the tensioner or the belt is stretched to it's maximum.
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
Good tight clean connection battery cables are just as important as the battery itself. They are approaching 20 years old; if you live in a salt-belt state... At least break them open at each terminal end, wire brush the block and frame/body connections to bright shiny metal and tighten securely. Once a year wouldn't be too often.