Battery light comes on and ligths dim @ WOT ?? - Ranger-Forums - The Ultimate Ford Ranger Resource


General Technical & Electrical General technical and electrical discussion for the Ford Ranger that does not fit in any other sub-forum.

Reply
 
LinkBack Thread Tools Search this Thread
  #1  
Old 10-01-2012
Member
Thread Starter
 
Join Date: Jan 2011
Location: kelowna, BC
Posts: 11
Icon5 Battery light comes on and ligths dim @ WOT ??

Hi Guys,

I have a new-to-me 2001 Ranger XLT stepside with the 4.0L and I have a somewhat strange problem. When I mash the throttle to pass slower traffic, around 3200 RPM and onwards the battery light will start to come on and flicker, and my headlights will dim slightly. There doesn't seem to be a loss of engine power at all but I was wondering what could cause this?

I replaced the battery about 2 months ago as the old one was shot. Is this possibly an alternator issue or something more serious? No starting problems and no problems below 3200 RPM. Let me know what you think, thanks!

TheBishop
Reply With Quote
  #2  
Old 10-02-2012
Member
 
Join Date: Jun 2009
Location: Bellevue, Nebraska
Posts: 6
Could be your belt tensioner going out, or the belt slipping, but more than likely it's your alternator beginning to crap out.
Reply With Quote
  #3  
Old 10-02-2012
Blhde's Avatar
Member
 
Join Date: Oct 2005
Location: Northern IL
Posts: 2,804
Pull the alternator and have it tested.

It could be the brush springs are weak or the brushes are worn out. Also possible the voltage regulator is bad.
Reply With Quote
  #4  
Old 10-02-2012
Member
Thread Starter
 
Join Date: Jan 2011
Location: kelowna, BC
Posts: 11
Quote:
Originally Posted by Blhde View Post
Pull the alternator and have it tested.

It could be the brush springs are weak or the brushes are worn out. Also possible the voltage regulator is bad.
I think that will definitely be the next step... My tensioner also squeaks, has a wobbly bearing and is needing to be replaced so between the two of them I think that would be the issue. Makes sense too if the belt starts slipping at higher RPMs due to poor tension.

I'll give that a shot and see what happens, thanks for the idea!
Reply With Quote
  #5  
Old 10-02-2012
Taylor's Avatar
Ive been dubbed....an old volk
iTrader: (18)
 
Join Date: Mar 2010
Location: Nashville, NC
Posts: 7,110
Keep us updated.

I had a similar issue recently, and certain vibrations from different rpms wiggled one of my grounds loose.
Reply With Quote
  #6  
Old 10-02-2012
01RangerEdge's Avatar
Scrambles the DeathDealer
iTrader: (11)
 
Join Date: Jul 2009
Location: Jackson, MO
Posts: 7,598
You were probably about to go back in time. This is why I have such a light foot, I don't know if I could handle myself time traveling.
Reply With Quote
  #7  
Old 10-02-2012
Scrambler82's Avatar
Old Guy Userů ltr
iTrader: (12)
 
Join Date: Jul 2009
Location: SoCal
Posts: 6,773
I had a 1998, had what I thought was an alternator go bad.
Opened the hood and the idler had almost fallen completely apart.

If you do a new alternator and getting the old one checked while out is a good idea, replace the idler and the belt either way.
.
Reply With Quote
  #8  
Old 10-03-2012
patkelly1336's Avatar
Member
 
Join Date: Mar 2011
Location: Elm Grove, Wisconsin
Posts: 209
Quote:
Originally Posted by TheBishop View Post
Hi Guys,

I have a new-to-me 2001 Ranger XLT stepside with the 4.0L and I have a somewhat strange problem. When I mash the throttle to pass slower traffic, around 3200 RPM and onwards the battery light will start to come on and flicker, and my headlights will dim slightly. There doesn't seem to be a loss of engine power at all but I was wondering what could cause this?

I replaced the battery about 2 months ago as the old one was shot. Is this possibly an alternator issue or something more serious? No starting problems and no problems below 3200 RPM. Let me know what you think, thanks!

TheBishop
My Ranger (2008 XLT, 4.0L SOHC) did this to me last year and eventually turned out to be the Alternator. When hitting the onramp to most freeways, I would floor it and when it would get to around 5900 RPMs, it would dim the lights, cause loss of power, and the battery light would come on. Turned out the alternator was losing current for some reason with the internals. $300 later and I no longer have that issue. (and this happened after I replaced my battery as well)
Reply With Quote
  #9  
Old 10-13-2012
Member
Thread Starter
 
Join Date: Jan 2011
Location: kelowna, BC
Posts: 11
Yup, well after taking my alternator to a local rebuilder he told me the regulator was bad and rebuilt the alternator for $100. After putting it back in the truck, i drove it for a few blocks and noticed the same issue. Frustrating. I took it back to the rebuilder and said "Hey, fix it! whatever you did didn't work." He looked a bit deeper and found a short in the 'fusible link' between the battery and the alternator. I honestly hadn't even heard of such a thing before and I'm a weekend wrencher who has rebuilt two engines on my own.

Regardless, he replaced a 15cm length of wire lead off the battery to the alternator and the problem is fixed. Only charged me $30 for his additional hour of diagnostics and searching. All in all a fair deal.

I also replaced the tensioner as the old one was squeaking and visibly worn.

Now to figure out if I need a new oil pump (on an unrelated issue) and then all my gremlins wil be gone :)
Reply With Quote
  #10  
Old 10-14-2012
fifthranger's Avatar
Member
 
Join Date: Oct 2007
Location: cleveland, oh
Posts: 198
Glad that you got everything squared away. I would imagine that a bad alternator would cause "battery draw" problems. I guess I got lucky when my 04 4*4 light lit up. I went to Advance to have the system checked, and I was told that it was the alternator. Ford wanted almost $500 to do the work, and I was out-of-warranty. Also, I was told that Ford used two different outputs for my year 4*4, and naturally mine was the more expensive one. Anyway, I bought a remanufactured alternator from Autozone, and paid a buddy to swap the old one out.
Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
1996 Battery light coming on, yet battery and alternator work' SariahLeah SOHC - 2.3L & 2.5L Lima Engines 2 06-04-2010 04:16 PM
battery light ABS light dim light RangerSkippyRoo General Technical & Electrical 3 05-25-2009 11:25 AM
WILL 01-05 TAIL LIGTHS FIT 2000 poor_boy_custom General Technical & Electrical 20 03-26-2009 07:43 AM
Battery indicator comes on at 4500 RPM JK1022 General Technical & Electrical 4 05-02-2008 05:57 PM
Battery Light Flashes at WOT WholesaleMN.com General Ford Ranger Discussion 15 01-14-2007 01:56 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

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 Off
Pingbacks are Off
Refbacks are Off



All times are GMT -6. The time now is 09:32 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.