Battery light comes on at high rpm...

[jfman]

My explorer started doing that this week. When I rev any higher tha 3100rpm the battery needle drops and the battery idiot light comes on.

Bad alternator ?

It only happens when I'm above 3100rpm. Other than that it's 100%. I try to keep it under 3k so it's really an issue right now but I think it may go our soon.

 

[Blee1099]

I would get the alternator tested.. Sounds like a load issue.

 

[jfman]

I see it getting weaker by the day. the needle is lower and lower and lower.... Looks like I'm gonna have to shell out some money for a new alternator...

 

[97greenmonster]

Sadly, your right.

 

[Blee1099]

Your probably looking at $130-140 for one without the core charge. If your in pinch, consider getting a used one from one of our vendors.

 

[jfman]

it's 110 from autozone... I'll just buy it from them. I also bought a new belt tensioner from ford(67$) while I'm at it I will replace it(mine is loose).

A well that's normal to spend a few bucks here and there on an explorer with 329k kms. I runs great so I'm keeping it alive ;D

 

[jfman]

I bought a new one for a diesel ford truck. 200amps baby !!

It's identical except it has one more groove on the pulley.