Check Charging System off/on

[jaxgriff]

2007 Ford Explorer 4.0L SOHC V6 2WD

The Check Charging System indicator recently came on while driving on a long road trip. After about 150 miles, the Check Charging System came on and would stay on for a minute or two, then go off. It would be off for a while, then return for a few minutes longer. This pattern occurred for the remaining 100 miles of the trip. The only other time I experienced the same symptoms was on the same road trip about a 6 months earlier.

I replaced the battery about 4 months ago. I tested the voltage of the battery and it appeared normal. I tested the alternator and the voltage was ok there. I brought it in to Advanced Auto Parts yesterday and had them perform the same tests and the results were the same. The battery and alternator are ok.

I have not seen the indicator since (it has been 2 days now) and we have been doing light driving around town, like normal.

I ran a diagnostic test with my OBD2 scanner and OBD Fusion iOS app. The results don't tell me a thing. I'll include them here just in case they might mean something to someone else. The test was performed while the SUV was in park and while reving the engine to approx. 1,500 rpm.

https://drive.google.com/file/d/0B-zMF6L4Bo6-SDd6THkxOVFYZDA/view?usp=sharing

Does anyone have any clues? The Advance Auto tester guesses it is possibly related to heat. Is this a possibility? fuse? voltage regulator? Is it possible that the indicator is a false positive? Any ideas would be greatly appreciated.

Mark

 

[BrooklynBay]

Welcome to this forum! There could be an intermittent heat related issue with the brushes or the regulator. Take a volt meter along with you on the trip, then pull over the next time you see the no charge indicator light to test the voltage of the electrical system.

 

[jaxgriff]

Hey thanks. Do you know if the brushes and the regulator are both internal on this alternator? I am not an alternator expert.

 

[Flag Gibby]

Yes, the regulator and brushes are internal on these models. I agree with Brooklyn, definitely sounds like a heat related issue. Also check the alternator connectors/wires and verify that they are not worn or very corroded. Also, make sure that your tensioner and serpentine belt are in good condition (don't think that this has anything to do with it since you would most likely hear the belt if it was slipping, but none the less a good thing to make sure is in good working order).

 

[jaxgriff]

Thanks for the quick reply.

I am looking at replacing the alternator. Do you know if it would be ok to replace it with a 130 Amp alternator? I think the one I have is 115 Amps.

 

[Flag Gibby]

Going up in output is fine, but never go less than the original amperage rating.

 

[jaxgriff]

Thank you BrooklynBay and Flag Gibby. Good Information.

The belt looks ok but it has not been changed in a while. I am looking to change it soon anyway. I looked at the connectors and they look pretty good too. I think I'll replace the alternator and serpentine belt for good measure.

Mark

 

[BrooklynBay]

An alternator rebuilder will have special test equipment for performing specific tests. The auto parts store usually has a general good/no good tester.

 

[Flag Gibby]

Thank you BrooklynBay and Flag Gibby. Good Information.

The belt looks ok but it has not been changed in a while. I am looking to change it soon anyway. I looked at the connectors and they look pretty good too. I think I'll replace the alternator and serpentine belt for good measure.

Mark

If the belt looks fine I wouldn't worry about it; it's the tensioner that I have seen fail the majority of the time.

 

[jaxgriff]

I replaced the alternator and the serpentine belt. The old belt was in decent shape but a little dried out, not much; I replaced it anyway.

The connector was actually corroded a little. I cleaned it out and put some dielectric grease on the connection prior to connecting it to the new (remanufactured) alternator.

https://drive.google.com/a/griffingang.com/file/d/0B-zMF6L4Bo6-TVBiRGtpWHM1QUk/view

I have seen mixed feedback on using dielectric grease on certain electrical connections. Is there anything seriously wrong with using dielectric grease on an alternator connector? Everything appears normal after installation.

 

[Ronin8002]

I have seen mixed feedback on using dielectric grease on certain electrical connections. Is there anything seriously wrong with using dielectric grease on an alternator connector? Everything appears normal after installation.

from what I understand, dielectric grease is mainly for adding some lubrication and water resistance to the rubber/plastic parts. It doesn't conduct electricity well so you want to avoid putting it on the actual conductor parts, but I doubt it would be a huge issue on something with a high voltage like a spark plug wire. The alternator harness is relatively low voltage so just don't apply grease directly to the pins/sockets

 

[jaxgriff]

Thanks. Do you know what type connector that is shown in the link to the photo in my most recent post? It is the small connector to the alternator, not the three pin connector. Is that the jumper? I tried to find it online somewhere and can not find the name nor the part number. I am wondering if I should replace it.

 

[Flag Gibby]

I wouldn't worry about replacing it, just use a plastic safe cleaner on it and maybe a little sand paper or a really small metal file in there to scrape off any oxidation on the metal prong and you should be good to go.

 

[BrooklynBay]

The auto parts store has electrical contact cleaner spray. Try some on the alternator's contacts, and inside the electrical plug.

 

[thebrakeman]

My V8 truck was doing this some time ago. Battery and alternator checked out fine at the auto parts store (standard test). Took the alternator to a rebuilder. Did not need a complete rebuild. $40 for a new voltage regulator (including new brushes & holder), and all is well.