yes, that’s a bummer. I don’t know how the other two big ones handle it (Autozone and Advance Auto Parts). Another cheap alternative might be to go for a used one from a junk yard or taking it to a mechanic who knows what he/she is doing.
[quote=“kurtwm2010, post:42, topic:95685, full:true”]
yes, that’s a bummer. I don’t know how the other two big ones handle it (Autozone and Advance Auto Parts).
[/quote]Except for the Valuecraft line, alternators sold at AutoZone have a limited lifetime warranty.
Too many times guys buy a part, keep it on their car, clean the old, bad, part, bring it to the store, and say they didn’t need the part, and want their money back, claiming their old part is the new part, which the don’t need
And then the next sucker buys that alternator, thinking they’re getting a rebuilt alternator. When in fact they’re just paying for somebody’s 20-year old non-functioning alternator
Not saying that YOU would do it, but plenty of people have low morals and would sleep well at night, after pulling that stunt
It’s far too risky for an auto parts store, IMO
No offense intended, but there’s always the other side to consider
You won’t measure a voltage between the alternator B+ post and the battery positive post unless current is flowing between them; i.e. the alternator is charging the battery or supplying current to power an accessory, like the headlights.
I’ve measured that voltage on my Corolla quite a few times when diagnosing charging and battery problems, around 0.1 to 0.3 volts is what it measures usually, if I do the measure first thing in the AM on first starting the car so the alternator will be giving the battery a little boost from sitting overnight.
hmmm … Be sure to set your DVM to measure DC volts. I usually use the 2 volt or 0.5 volt scale. Then put one DVM probe on the alternator B+ post, and the other on the battery positive post. The engine has to be running of course, otherwise the alternator won’t be producing any current to flow in the wire.
I think it’s great you took the time to do the experiment @ok4450 , but it is confusing to me why you measured 0 volts. Sometimes I can get a bad connection between the probe and one of the posts b/c of corrosion, that may be what’s happening in your case. Double check the probe is making a good connection by measuring each point to battery ground or a chassis ground maybe first. If you get no voltage then, you know you aren’t making a good connection.
hmm … what else could be causing yoru 0 volt measurement? Well, if the battery was already fully charged then the alternator wouldn’t need to charge it, so you might read 0 volts. Try turning a bunch of electrical equipment on maybe, like the headlights on bright, the rear window defroster (if you have one), heater blower motor to max, etc. Maybe that will be enough to kick the alternator into charging mode.
And maybe somebody else here could try it on their cars, report what they measure.
I purchased a rebuilt starter motor one time from a national parts chain and it didn’t work, and they gave me that line when I took it back for a refund. The verified the one they sold me tested bad. At first the staff there said the only remedy available is they’d replace it with another one. That didn’t work for me though, b/c I’d lost faith in their process. I mean if they had the capability to test it, why didn’t they test the one they sold to me the first time? Anyway, I went back and forth with the manager there and eventually we came to a compromise where they’d credit me the full amount with a store card which I could use for future purchases. I used that to purchase consumables, oil, coolant, and the like, so it worked out ok for both parties.
Testing the integrity of the alternator to battery circuit is a part of the diagnostic procedure. A problem in that circuit usually only occurs if someone connects jumper cables incorrectly.
About 5 years ago I couldn’t help but notice a co-worker replace an alternator on a car with less than 10,000 miles on it. The next day he replaced the battery, then 3 days later the PCM. The last thing he replaced was the 140 amp charging system fuse, that was a $2,000 fuse. I had confirmed that this company hires people that can’t use a DVOM or apply practical diagnostic procedures.
I disagree. Alternators go dead all the time. Wires inside start melting and fusing together, diodes have a tendency to burn out (resulting exactly into the problem the OP is having), and the voltage regulator burns out frequently.
You don’t have to count them, just look on the right side as you scroll upward. Post count is displayed there. Although I would prefer a new post, it’s not all that difficult to find the one he edited…