Battery Light

[WoodBoy]

My dad's 01 F250 had the battery light come on today. We have load tested both batterys, they were good, we checked them with the engine at idle and both were in the 14.5 range so the altenator seems to be putting out. The light doesnt flicker or anything it just stays on. Any help would be appreciated


He had no CEL, but I ran for codes anyways and got a P0603 code. I went ahead and cleared it, cranked the truck and the battery light was still there so I switched off, ran for codes again and no codes were present. So apperently the code and battery light must not be related but anyone know what I need to do about this code? Just wait and see if it comes back up?

 

[7.3psd97444]

That is a common code. It can pop up just from disconecting the batterys. Is it tuned? Also pops up if you load a superchips type tune thru the obd. Prolly not the issue.

As far as the battery light goes, check the connection of the wires on the altenator. If that connection jiggles, loosens or moves around someway, the battery light will come on. Even tho the batterys and altenator are all good. Mine did on my OBS from a water line rubbing the top of it. Moved the line and sturdyed the connector and it was fine.

 

[WoodBoy]

It is tuned with an SCT programmer. We wiggled the connector on top and didnt see a difference but I will check it again.

 

[gman1]

See if this helps.
If the cluster light goes off when you unplug the alternator, then the problem IS NOT between the alternator and the cluster. So you're either looking at a supply voltage issue or an alternator/connector issue. Use a test light to see if you have 12 volts at the "A" terminal (orange/lt. blue) wire with the key in the "run" position. If you have 12 volts there, then the problem is at the alternator (be it the connector or the alternator itself. If you DON'T have 12 volts, check the #6 fuse under the hood.

 

[JLDickmon]

if you get 14.5v w/ the engine running, and the light is still on, most likely you have a problem internally in the alternator.. open phase, grounded diode, etc..

if you have access to a lab scope, you can see it in the ripple pattern..

Pop's P0603 is most likely from the programmer..

 

[JLDickmon]

hey.. onething you should do at some point, is pull both batteries and load check them seperately..

 

[WoodBoy]

Both batterys were seperated when tested. My dad said he found a blown fuse and that fixed it

 

[gman1]

Both batterys were seperated when tested. My dad said he found a blown fuse and that fixed it

#6 fuse?

 

[WoodBoy]

I really aint sure. He just told me it was a 20amp fuse

 

[lincolnlocker]

check voltage again... idle voltage should be just over 14v and under 14.5v.

 

[TARM]

My guess would be a ground issue with the alt.

907Dave is good with funky electrical issues.

 

[907DAVE]

Yup, a poor body ground can cause all sorts of issues, including a battery light. Connect the negative lead of a volt meter (set to DCV) to the battery negative post and touch the positive lead to numerous places around the the firewall and fender, should read 0 volts.

Before you check that I would disconnect the alt and see if it still charges, thats a dead giveaway of a failed regulator.