Electrical Problem, batery light on

[misho]

Hi guys, i have a 99, stock Ford explorer 4.0L, OHV, 5 speed manual.

Today, i noticed that revving the car at above 2600RPM, the volt meter (or ammeter, as i read in another post??), starts to go low and the battery light will turn on/flicker. This is at about 2600RPM.

The car has 170,000km on it, don't know if the battery and alternator were changed before.

What could be the problem? Battery or alternator? I am gonna check out the voltages later today and see what i get.

Can this 2500-2600RPM problem be because 99% of the time I drive the ford on the highway at 110km, which is about 2500RPM in 5th gear? , well 99% of the time within the past 30,000km.

Oh and also, i am gonna try running the car with heater, music, lights etc at full blast and see if the voltage needle drops.


Thanks!

 

[ponch68]

Sounds like your already on the right track. It could be either one, but from the sounds of it I go with your alternator or maybe even the voltage regulator. I'm not sure if it's an external voltage regulator or internal to the alternator. Most auto parts stores can do a check of your charging system and diagnose the problem before you go tearing into it. I don't think it's your battery. Good Luck!

 

[misho]

Hey guys, so I was driving right now and did a little test

With the heater on full blast, revving over 2500rpm was fine, the needle didn't move, and nothing was wrong.

With the heater on low/medium, the needle did move after revving over 2500RPM.


Starting the car is the same, i don't find any loss in power.
Gonna go check the voltages and see what they show.

Seems like its an alternator problem.

 

[manaen]

sounds like your regulator may be on the way out. As long as it is supporting a load and keeping your battery charged I wouldn't worry too much. Just keep an eye on it.

 

[misho]

so today i start up the car, (starts fine), the battery needle is at low, and batery light is on/flashing,

its definitely the alternator. i doubt the car is gonna start tomorrow lol..

 

[manaen]

have your alternator tested, you should be able to find an electrical place that will rebuild the unit fairly cheap.. (less than 80)

 

[misho]

have your alternator tested, you should be able to find an electrical place that will rebuild the unit fairly cheap.. (less than 80)

Yea it was the brushes on the alternator, one was very very wasted, so it barely made contact.

Got them replaced and everything is fine now.

Thanks

 

[manaen]

Excellent!! thanks for updating the thread with your result. This will help others in the future...