Electrical problems on a 1999 ford ranger xlt
 

I have been having electrical problems on my truck recently and am looking for advice.

About a week ago the voltmeter on the dashboard went all the way up to the red line at H(igh), so I turned off the radio and went home (it was less than half a mile from where I live) and used a different car. The next day I went to autozone which did a diagnostic on the alternator and said it was fine, but they said the battery was weak. So I bought a new battery (my old battery I bought around Dec 2005, so I figured it was time for a new one).

Now the voltmeter is reading low. It is still within the white brackets, but the voltmeter reading is in the bottom 1/3, so I'm guessing 10-12 volts.

When I shut off the engine and only turn the key enough to engage the electrical system w/o turning on the engine the same reading comes up, bottom 1/3 of the voltmeter.

I took it to a mechanic and he said I needed a new alternator. But

1. If I need a new alternator why did the diagnostic at autozone say the alternator was ok? I don't know what they did, but I assume they were asking me to rev up the engine to see if the alternator was putting a charge out.
2. What amp alternator would a 1999 ford ranger XLT 2.5L 4cyl AT w/o power anything (no power windows, locks, seats, etc) need? I don't know if it takes the 95amp or the 130 amp.

I've heard it may be the voltage regulator, but that is part of the alternator. I don't know jack about cars so I have no idea what all diagnostics they did at autozone (they just hooked up a computer w/jumper cables to the car and told me to run it at about 2-3k rpm).

Definitely sounds like the alternator. Possibly when it was tested first time it was putting to spec. Have read similar thing here before where it performs at some RPM's and not other due to worn brushes and defective voltage regulators. From what can tell on Ford Parts website (Part 10346) it seems it's a 95 amp unit. Make sure you get a good replacement with a decent warranty. If you replace it yourself disconnect battery terminals to avoid shorting anything out in the changeover.

Buy 1999 Ford Ranger Parts | FordParts.com

Thanks. I don't know how much longer the truck will last since it is starting to have other problems (transmission problems as an example) so I am mostly just looking to get it to last another 2-3 years or so.

I am checking car-parts.com and ebay for alternators. But I don't know which is a good brand, and I'm worried about buying some cheaply made alternator.

Would buying new, remanufactured or salvage make a difference for the new alternator? The prices on the new one are all over the place (from $69-$250), and I don't know what the difference is, and I don't want to buy one that'll be poorly made, and I'd rather not spend $200 for a new one if a $50 salvage one with 70k miles will work. I am a novice at best at this stuff.

I'm guessing a grade A salvage part with less than 100k miles and a 6-12 month warranty might be a good bet, those are $50 or less.

I wouldn't go the salvage route cause may not be any better than what you have. Here is a link to advance if you want to check pricing.. Another option would be to check out yellow pages and see if anyone in area could rebuild your present one. Don't know what would cost but it's an option and you get estimate and compare price to rebuild. You probably only need new brushes and a voltage regulator providing your bearings are sound. Never have rebuilt one so not sure how difficult would be.

Advance Auto Parts: Search Results for 95 amp alternator