Alternator or regulator?

"Snuffy "Hub Cap" McKinney" wrote in message news:... The charging circuit on the 97 Aerostar finally failed completely. The current had been cycling when running and headlights were on, but was too intermittent to get it checked out. I drove it 1/2 hour today, no problems starting or running. Parked. Then a couple of hours later went out to start it, engine turned over slowly and then slowed to a stop without starting. Tried again and the solenoid was chattering. Did not notice what the ammeter read before it went dead.

I then put charger on the battery. 2 hours later, it cranked right up. While idling,I saw that the ammeter indicated it was discharging about midway between far left (discharge) and mid-point.

I'm letting the battery charge over night so I don' t get stranded while running for parts.

Now what I need to know - how to isolate the problem to the alternator or the voltage regular. Also, if it's one or the other, how difficult is it to r/r myself?

Would you recommend having O'Reilly's check out the alternator or regulator?

*** Or better yet, how can I isolate it? I remember taking a car to O'Reillys years ago for the same problem. They put the meter on it and said right away that the alternator was bad. I had the local shop change alternators, but then the old unit checked out good. The problem had actually been loose connections at the alternator.

On Sat, 1 Oct 2016 22:22:29 -0700, "Snuffy \"Hub Cap\" McKinney" wrote in

Why not just take it to a local shop to begin with?

From past experience I'd say replace the alternator - complete with the integrated regulator. I changed the regulator on my old aerostar twice for that same problem - when I finally replaced the alternator the problem went away. he brushes were OK and the diodes tested OK, but the charge rate was still intermittent. Theoretically a regulator should have fixed the problem and I highly doubt I got 2 bad regulators from 2 different sources. I was fortunate to find a quality rebuilt alternator at the wreckers - had just been installed a few weeks before the van ended up totalled. - for less than the cost of another regulator.