Battery light - 11.3 volts

[ExplorerTom]

Driving home tonight my battery light was on. I flipped my ScanGauge over to Volts and it was showing 11.1-11.5 volts depending on RPM.

Every other car I've had prior to this pointed immediately to the alternator because the voltage regulator was integral. Now I see I can replace either on this truck- at least so says my Haynes manual and O'Reilly's website.

Both components are of unknown age.

How do I rule out one vs the other?

 

[Bedrck47]

Yes you can just replace the Voltage Regulator
What is the mileage on the expy and keep in mind that if the miles are high then you would also want to replace the bearings and brush assembly

Just changed the alt on my 2001 and it is very easy to replace just 3 bolts hold it in place Best to remove the Radiator Hose to have better access.
Remove neg battery cable from battery.
Loosen the serpentine belt

 

[ExplorerTom]

181,000 miles. 2000 5.4l

 

[Bedrck47]

Just an opinion but with winter coming I wouldn't wait too long to make the repair

 

[ExplorerTom]

Go with the full alternator?

I've had it out while doing the intake manifold. It's easy. I might also do the serp belt and give all the pullies a good look while I'm at it.

 

[Bedrck47]

That's what I would do.

 

[ExplorerTom]

Well I moved it into the garage. Might be able to work on it tonight. Tomorrow isn't looking good because I am going wheeling all day.

 

[stamp11127]

You may also want to check fuse 11 in the Battery Junction Box. If that pops you will not get power to the field coil and the alt will not have an output.

You should also have battery voltage on the alternator output stud and ground with the engine off.

 

[GAINMOB]

have orielly...napa...autozone...etc...check them...they can use their tool to test both...i would replace the batter no matter what...find out if alt is bad or going bad before u do

 

[ExplorerTom]

Well alt and regulator both tested good. Twice.

Still looking......