My battery does not seem to be recharging. I've had the battery tested and it checks out as ok. The alternator tester (done with a device connected to the battery terminals while the alternator is still in the car) read that the alternator regulator is bad. We replaced the alternator with a rebuilt one and am still having the same problem not charging the battery. When I turn on the electronics the voltage steadily drops. Also, there doesn't appear to be a drain on the battery because the voltage doesn't seem to drop overnight. They tested this "new" rebuilt alternator, again while still in the car, and got the same message that the alternator regulator is bad, not putting out enough amps.

I'm not about to discount the possibility that the rebuilt alternator is in fact defective, and they have another one coming in tomorrow morning at which time we will put both on the tester in the shop. However, I was wondering if something else could cause this problem that I could be checking for in the mean time?

Thanks in advance for helping out the rookie mechanic. Everyone here has been great.

 

Sorry, forgot to mention it's on an '85 300SD.

 

Who checked your battery, sold you an alternator, then tested it to be good?

Who are we dealing with here?

 

O'Reilly's tested sold me the alternator, tested it as bad, tested the battery as good.

 

Sounds like an independant repair shop, I'd say give them a chance to prove their diagnosis and make the thing work. You paid for the repair now they must effect it.

However if this is just a parts house selling you parts then you need to get to a trained technician who can properly test, diagnose and repair the system, otherwise you will just be chasing you tail I'm affraid.

 

O'Reilly's is a large chain of parts stores throughout the midwest.

 

Points to ForcedInduction. I got the multimeter out and traced the problem back to the pigtail wiring bundle that plugs into the alternator, it had a broken wire. I spliced the wire and things are working again. The new part will be in tomorrow.

In O'Reilly's defence, they are a parts store, but my alternator guy who was just down the road went off and retired to Florida (darn him). The next closest alternator shop is 40 minutes away. The alternator and battery are under warranty from them, so I was hoping one of them would be the problem and I could get off at no cost. This particular O'Reilly's has gone way out of their way to be helpful to me over the years, which is why I go there instead of the parts shops that are closer. But I realize the limitations they have in diagnosing stuff, which is why I didn't assume they were correct and also why I love this forum!

Thanks again guys.