Intermittent charging system light - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars
Ford Explorer | Ford Explorer Sport Trac | Mercury Mountaineer | Lincoln Aviator Forum for discussion of the Ford Explorer, Ford Explorer Sport Trac, Mercury Mountaineer and Lincoln Aviator.

 
LinkBack Thread Tools Display Modes
post #1 of 8 (permalink) Old 10-03-09, 11:03 AM Thread Starter
Registered User
 
Join Date: Jan 2006
Posts: 46
Intermittent charging system light

Intermittent charging system warning light. Just started - mostly at low RPM. Battery gauge is still centered and volt meter across battery with engine off is about 12.3V. This is a 2002 V6 Explorer XLT with 142,000 miles and the origninal battery. Is this a case of the alternator ready to die? Or what are other possible causes? How do I diagnose it?

NCVinVT is offline  
Sponsored Links
Advertisement
 
post #2 of 8 (permalink) Old 10-03-09, 12:20 PM
2002 F150 XLT
 
Bert's Avatar
 
Join Date: Nov 2008
Location: Oregon
Posts: 10,312
Re: Intermittent charging system light

It could be a poor connection in the system somewhere. What voltage did you get with the engine running?
Bert is offline  
post #3 of 8 (permalink) Old 10-04-09, 02:25 PM Thread Starter
Registered User
 
Join Date: Jan 2006
Posts: 46
Re: Intermittent charging system light-more symptoms

With engine running and fan and headlights on, voltage across battery is only 11.2V; with fan and headlights off it is 11.5V. Should be 12.8 to 13.5 V, right?

Now when engaging starter motor the dashboard gauges goes wild - speedometer and tachometer peg out at high end of scale, then drop back when return key returned from “start” position to “on” position.

Loose ground somewhere?
NCVinVT is offline  
post #4 of 8 (permalink) Old 10-04-09, 03:15 PM
2002 F150 XLT
 
Bert's Avatar
 
Join Date: Nov 2008
Location: Oregon
Posts: 10,312
Re: Intermittent charging system light

With the engine running you should have around 14.2 with a fairly charged battery. Sounds like you have charging system issues. Check all the connections and you could take the alternator to have it tested at a parts store that does that dor nothing.
Bert is offline  
post #5 of 8 (permalink) Old 10-06-09, 05:12 AM Thread Starter
Registered User
 
Join Date: Jan 2006
Posts: 46
Re: Intermittent charging system light

Test proved alternator not charging. Trusty mechanic replaced with a rebuilt alternator, replaced 7 year old battery and pulleys. System is charging fine BUT the dash idiot light remains glowing. What is that from and how do we fix it?
NCVinVT is offline  
post #6 of 8 (permalink) Old 10-06-09, 08:24 AM
2002 F150 XLT
 
Bert's Avatar
 
Join Date: Nov 2008
Location: Oregon
Posts: 10,312
Re: Intermittent charging system light

Check fuse #15 under the dash and if that's okay, it could be a defective alternator or plug to it. The light green/red wire controls the light.
Bert is offline  
post #7 of 8 (permalink) Old 10-08-09, 04:48 AM Thread Starter
Registered User
 
Join Date: Jan 2006
Posts: 46
Re: Intermittent charging system light

Thinking the rebuilt alternator may have been defective, my mechanic installed a second rebuilt alternator. But after 2 miles of driving, the charging warning light returned again. Voltage testing and computer scan show it is charging fine. He suggests that there could be a problem behind the dash. He notes that the voltage gauge never moves but it should wiggle when load is applied - like fan on with headlights. It has always remained very steadily centered after ignition start I tell him. Also we checked all fuses. Mechanic says plug and connection are fine. Besides friction tape to cover the idiot light - how can I diagnose / fix this problem? I realize if the alternator conks again I won't get a fair warning under present status of the electronics.
NCVinVT is offline  
post #8 of 8 (permalink) Old 10-08-09, 08:09 AM
2002 F150 XLT
 
Bert's Avatar
 
Join Date: Nov 2008
Location: Oregon
Posts: 10,312
Re: Intermittent charging system light

The battery gauge doesn't move very much. You won't see a jump when somethimg is tuned on. That green/red wire is the wire to the light. They should check that wire and it's circuit.
Bert is offline  
Sponsored Links
Advertisement
 
Reply

  Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars > Ford Trucks | Utes | Vans |SUVs | Crossovers > Ford Explorer | Ford Explorer Sport Trac | Mercury Mountaineer | Lincoln Aviator


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome