1998 Ford Ranger - BATTERY LIGHT?!?

On Wed, 19 Dec 2007 00:48:09 -0800, snewman1209 rearranged some electrons to say:

Alternator is bad, or belt is slipping.

My Battery Light came on, and the problem was the alternator brushes.

The battery light is really a Charging System light.

There is a set of brushes that are easy to replace, and can be found at NAPA. I looked them up on napaonline.com. Your alternator should be similar, if not identical, to mine, but I have a '97 F150 so it _could_ be different. I expect it to be the same.

I'm not sure if you can replace the brushes with the alternator in place, I took mine off for the service. I was expecting to replace the alternator, but found the cost to hover close to $200. I looked at Autozone, Kragen, and Pep Boys (all online) before I searched NAPA. The NAPA site listed a couple of dozen hits to "alternator", and the brushes were at the end of the list. There are brushes that you have to figure out a way to attach, and there is a brush set that comes with the mounting block and all connections. I bought the one that came with the block, and it was very easy to replace. The part I bought only cost about $15 and took more time to buy than to install.

The brushes are spring loaded to press against the armature of the alternator and collect the electricity and deliver it to the nether reaches of your truck. You are describing the affects of having a brush (there are two of them) that is worn down, and not contacting the armature very well at high speed.

I could be wrong on this, but all you need do to find out is pull the alternator and take the screws off of the back to remove the diode pack and brush assembly. It is really a very easy job, but the screws are torx so you may need to buy a torx driver set.

Wow! thanks for the info! A lot of read over, but figure its worth doing in house. VERY appreciative!

Thank you!

Go to napaonline.com and plug in your truck, then search for ALTERNATOR. You be flooded with hits for new and rebuilt units, 95 and 135 amp. Scroll to the bottom of the list and you will find the brushes. I took a pass on the two individual brushes because I could not determine a clean way to connect them. I did find a brush assembly, with brushes and the housing all pre-assembled. It was a direct replacement to the assembly that came out, and the entire job took more time rounding up the parts than putting them in. The brushes appear (in my case) to be the same for all applications of alternator, and since I have the XLT with air conditioning and trailer package, I assume I have the 135 amp alternator. I do not recall any indications on the alternator as to the output specification.

Call your local store because they might have to bring them in. My store had a set or two on hand ...

^^^^^^^^^^

True of a generator, not true for an alternator.

Yes. That part of his statement is in error. The brushes in an alternator do not carry output current.

That the brushes are worn and bouncing off the slip rings? Common failure.

There are brushes. I replaced them.

They do wear down. I replaced them. Mine wore all of the way to nubs that were perhaps 7mm (1/4") long, and resulted in failure of the brush to reach the armeture (which, in a generator device is actually a commutator). I am predicting that the OP's brushes are worn to the point where they can stick in the channel that holds them, and this causes the contact to be broken; which causes the Charge Light to flicker at high speed.

The carry current to the diode pack that converts the output to DC, and perhaps provide regulator services as well.

I do not know what you know, but I do know what I know, and what I know is that I replaced the brushes in the alternator of my '97 Ford F150. You can argue with lots of stuff, but you can not argue with what I did to my truck.

I notice you haven't a better idea. The OP can test what I suggested by simply removing the alternator and taking a couple of screws out of the back. I could be wrong, but it will not cost anything to find out. And, if I am not wrong, I will save him roughly $175, and all he has to do after taking the alternator off of his truck -- a task he has to do anyway -- is take out a few screws and swap the part, then put the screws back in.

POINT OF ORDER I am not the one that said this was a common failure. I only said I had a similar problem as the OP, except I did not notice I had a problem until I needed a flatbed truck to get home -- he noticed when he hit the upper limits of the tach. Since I never hit the upper limits of the tach, I did not see the impending doom until it was too late. My point is not that the alternator is bad, my point is that IF the alternator is bad, it is easily fixed by swapping in new brushes instead of replacing the entire alternator at a significantly higher cost.

Never said otherwise.

Yes they do.

No dispute from me.

In an alternator, it's called a "rotor." The part that the brushes contact on the rotor are the "slip rings."

Which indeed -do- carry output current.

The tie in to the problem only occurring at higher RPM is what then?

Nope. The diode pack is connected to the stator, current is built in the stator as AC, the diodes convert the AC to DC. The brushes transfer voltage to the rotor making the rotor a magnet. Spin a magnet (the rotor) near a coil of wire (the stator) and current is generated. Some alternators with integral regulators use a diode trio to tap voltage directly off of the stator to feed the rotor thru one brush terminal, the other brush terminal is toggled to ground by the voltage regulator to control output voltage. (explains any diodes you may have seen connected to the brushes)

But I know what you know and I know that the brushes in an alternator carry field current, not output current.

Your dissertation should have ended there.

I'm not arguing with what you did to your truck, I'm stating that the brushes you replaced do not carry output current to the "nether regions" of his truck, your truck or any other Ford truck.

Because I don't disagree that replacing the brushes is a reasonable first step.

All well and good but it doesn't change the fact that the brushes do not carry output current which was the -only- thing I was correcting you on. If your ego is such that you can't stand a simple correction and use the learning experience to your advantage, well, life will get harder before it gets easier.

Duh! I did.

No, you didn't "only said." You said; "The brushes are spring loaded to press against the armature of the alternator and collect the electricity and deliver it to the nether reaches of your truck." Sorry Jeff but that is flat out wrong. Alternators do not have "armatures." The brushes only carry field current to the rotor. The brushes allow the spinning rotor and its windings to become an electro magnet

And that's a good point. I have no problem with your recommended repair, just with a small error in your theory.

Whoa guys! Seriously though, sorry to cause the bad blood here.....

But seriously, both you guys know your S#%T more than I, and appreciate all the information.

OP = Org. Poster...... got it! =)

Yes, Original Poster.

I don't know precisely what the brushes do that we are talking about. What I do know is that the alternator produces electricity, and your engine needs that electricity. The only way I know of to get the electricity out of the alternator is via the two brushes that I _think_ you will find that you need.

There's no bad blood here.

I know my shit. Strickland apparently comes from the ilk that bemoans the lack of trained knowledgeable mechanics but then recoils when he encounters one.

How in the world would you arrive at such a conclusion?

To what?

CRUD!!!!!!!!!!!!! I went to Napa this weekend, and they had the brushes in their computer, but not available in the WHOLE bay area. WTF?

Then I went to Kragen and they had no idea what I was even talking about.

Last night, driving relatives homes, my battery light pretty much stayed on (no flickering anymore) and my radio burnt out, all my dash lights came on, dome light shut off, and battery guage super low. So Im guessing the alternator just hit its RIP.

Now I need to ask........ is THIS a job I can do? Its more of a matter of betting the belt off/on yes? 10-15 mins?

It's an easy fix. Well, it was easy on my F150 with the 4.6L V8. I can't imagine your Ranger V6 will throw out any huge obsticles.

You said, not available. Do you mean not available, or not in stock? Not in stock means they can get them in a day or two.

According to Napa Online, the part number you need is ECHF424, and costs $13.99 (prices vary inside the store).

As I recall, this is the same part I needed for my F150, and is used on both sizes of the Ranger V6.

On my way back to napa today my truck finally shut down. Lost all juice.

I towed it home, and went to Napa and just bought a new (reman) alt. to replace. I dont have good light, so I may take the day off and try to tackle the mess tomorrow.

So far: disconnected the battery and thats it! LOL.... Im a little worried that im in over my head. but maybe not. Napa told me that once replaced, I should recharge the battery over night (or whenever I do it) so that I dont fry the new alt., since Im starting with no juice at all.

F&^( maybe its worth just paying the $$.... but I wouldnt be able to live with myself.... LOL

While it is off, take the torx screws out from the back. The diode pack will come off and the brush assembly is part of it. a couple more torx screws and the brushes come off of the diode pack. In any case, if the brushes are worn down, this is your problem.

I don't recall which motor you said you have, and I assumed the V6. The alternator brushes are available for both V6 motors, but not (as far as I can tell) for the 4.