Battery Light

[Jdlarobinson]

I know this sounds weird, however my wife's 2007 Expedition has about a hundred and eighty-five thousand miles. The last six or seven times we have taking it to the coast car battery light comes on. It goes off eventually. When we have it at home and she drives it to and from work the light never turns on. We have had a new alternator put in and a new battery. She drove down last Sunday and Monday morning she went to the store and the battery light came back on. This is baffling. Any help?

 

[Don Hall]

https://www.cars.com/articles/why-is-the-battery-light-on-1420663031640/

 

[Jdlarobinson]

But why only at the beach???

 

[Keepinitoldskool]

Battery light is triggered by the alternator so corroded/damaged wiring or dying alternator

 

[Alwaysthinkin]

More salt in the air near the ocean which is known to be hard on electronics among many other things. Not sure why you are having this issue, but since you have replaced alternator and battery it seems likely a poor connection is being made worse with the salty conditions.

 

[Don Hall]

"More salt in the air near the ocean which is known to be hard on electronics"

Have lived about 200 yards from the waters of Monterey Bay (CA) for about 64 years of my adult life, and haven't experienced any salt problems with electronics, or body rust. That doesn't mean salt is your friend. From afar, I'm betting on degraded/faulty components, cables, fasteners, etc.

 

[Alwaysthinkin]

Yes, specifics do matter. Everything you say is true for California, however OP has listed North Carolina as home. Talk to folks on much of the east coast to include the Carolinas, Florida, Louisiana, parts of Texas, etc you will hear a different story. All above my knowledge base but has to do with wind patterns and humidity among other things. California is blessed with some wonderful weather not everyone enjoys.

 

[Plati]

You dont say when the problem started or if it started after replacing alternator & battery or if you charged the new battery... and any other diagnostic information.

New batteries usually need to get a full charge.

I had a problem similar to that (vague details). Turns out the new alternator was bad. Battery light would come on sporadically for weeks and if I ran headlights battery would run down & not start engine. Diagnosed by measuring battery voltage 1) at rest engine off 2) while starting Expy 3) engine running, small electrical load 4) engine running, all lights and fans on.

Alternator could not handle a load like headlights.

 

[Jdlarobinson]

Sorry. This started 6+ months ago. We started out by replacing the alternator. Kept occurring so we replaced the battery. Happened again 3 or 4 times since.

 

[Plati]

If you have a good digital voltmeter, run that test and report voltage readings. That can indicate root cause (not always). The voltage drop while starting is fast , gotta catch it at low point.

Another cause can be the computer (PCM I think). It sends a waveform through the harness to the alternator to signal how much voltage generation is required based on battery state and loads on the system. You need an oscilloscope I think to observe that waveform. Also, as MrSchool said ... clean solid electrical connections are required for all that to work. I suppose there can be other issues but these are the most basic. I'm not an expert by any means but I have had the problem and it was a bad (brand new) alternator and had to be diagnosed with actual data. Once it was diagnosed, alternator was replaced (again) and fixed problemo. Hard to diagnose over Forum, need to observe clues in real life.

 

[Alwaysthinkin]

Check out this post on another thread, don't miss the first sentence about having your alternator tested at parts stores. Probably the first thing I would do...

Broke down abroad - alternator?

Hi everybody, We're currently camping, albeit sort of against our will. The Expedition was doing fine this whole trip until today when we stopped at a visitor center - tried to start it, dead battery. Got a jump from a kind RVer, which lasted all of about 2 miles counting how far we coasted...

www.expeditionforum.com

 

[Jdlarobinson]

Alternator has been replaced

 

[Alwaysthinkin]

Alternator has been replaced

Let us know how things go on your next run to the coast. Safe driving!

 

[Jdlarobinson]

Been back a week. Light has not been on a single time. Heading back tomorrow...stay tuned.

 

[Flight-ER-Doc]

Have lived about 200 yards from the waters of Monterey Bay (CA) for about 64 years of my adult life, and haven't experienced any salt problems with electronics, or body rust. That doesn't mean salt is your friend. From afar, I'm betting on degraded/faulty components, cables, fasteners, etc.

In my youth, I lived right on the beach in Venice (2nd house from the Marina Del Rey channel, beach out the back door). Especially in the winter, the salt effects are horrible. YMMV. Salt (in the ocean, or scattered from snow trucks) is horrible for cars.

 

[Jdlarobinson]

Update: we arrived at the beach yesterday afternoon. As soon as we turned the truck on this morning the battery light came on. Stayed on for about 5 minutes and has since gone back off. Totally confusing