Alternator?

[OdinAF]

So I was driving my 93 4.0 down the road and then I noticed my battery light was on, the lights and engine wear still running, but the lights where dimm.

First thing I'm thinking is alternator and I'm running on the battery,

So I get to destination and I check the voltage with the truck running and its sitting a little bit above 12V, So I'm thing Voltage Regulator?

There appears to be NO damage to the alternator internals unless its a warn out thingy ma bobber...brushings?

Thoughts?

 

[4.0B2]

Have an advance auto nearby?
Can go by there and they can put their fancy machine on it and check it. Advance usually has a better machine than AZ.

What is your battery on not running vs running? I'm gonna say the alternator is bad

 

[OdinAF]

Unloaded is 12.7V, loaded is 12.1V, just debating doing the 130A swap or this 140A from these guys.

http://www.autozone.com/autozone/pa...izrifZ9ci9i?itemIdentifier=352091_55002_4442_


I can use any alternator from a 93-2001 bronco,ranger,explorer with the 130A, right?

 

[RonD]

Battery voltage with engine off should be 12.5-12.8v
With engine running 13.6-13.9v

A 12v battery needs 1.1v above it's at rest voltage to maintain a charge, above 1.2v to recharge it.
12.7v at rest means battery is fairly new.
Yours should be at 13.8v at idle if alternator was working, so you are "running on the battery".

read here for the ones that will fit:
http://www.therangerstation.com/tech_library/alternator.htm

 

[Mudflap]

Isn't there an alternator fuse in the power distribution box? If you have your owner's manual, it will tell you if there is and where to find it. Quicker, and cheaper, than replacing the alternator.

 

[Andy D]

Isn't there an alternator fuse in the power distribution box? If you have your owner's manual, it will tell you if there is and where to find it. Quicker, and cheaper, than replacing the alternator.

Low voltage isn't a blown fuse . NO voltage is a blown fuse.

 

[OdinAF]

swapped alternator with a 140amp, works fine now, took the old alternator apart, brushing look great, probable voltage reg.

 

[RonD]

Thanks for the update

 

[doorgunner]

Thanks for the update

Repped the update!

 

[kf8xo]

On that same note...

Got the battery light and low voltage. Threw an Alternator in it and battery light went away and volt meter showing normal range. Six days later, battery light is back on, voltage showing discharge. AZ checked it on the truck and said Alt. was bad. Pulled it and took it to Pep Boys and O'Reillys. Off the truck it's putting out 15.2 nominal. Battery is also brand new. What do I look at next? I'm seriously ready to dump a grenade in the tail pipe.

Thanks guys.

 

[97ranger xlt]

did you get autozone/similiar to do a load test on the battery?

 

[amarino23]

looks like you got it but for future ref when properly charging you should be around 13.2 min and 14.6 max with the truck running

 

[kf8xo]

Installed new battery after the light came back on, and it resulted in no change. I've cleaned the pigtail connections, checked the connection between the alternator and the battery and it is good. Nothing burned out in the distribution block.

And AZ load tested the new battery and said it was fine.

 

[97ranger xlt]

i think you need to pull that alternator and get it bench tested again. i have had 2 machines give completely different results on one i had. one bad one good. ended up bad was right. so i say get it tested again.

 

[kf8xo]

Well, I had it tested at AZ in vehicle, showed bad. Tested on the bench at Pep Boys and O'Reilly and tested good...guess I can pull it and take it over to Advance...