Hello.
I'm still not totally confident in my skills as a mechanic, so I'd like to run something by you all just to confirm that I'm either on the right track or completely wrong.
My car is a 92 Jetta, 1.8 gas w/AC. Around 230,000 km, and still treating me right...most of the time.
Today, out of the blue, my alternator light stays on while the engine is running. It actually seems to "flutter" really fast, rather than just stay full on. I ran through some tests:
-Battery is fine. It's fairly new, still shows 12V with engine off.
-Alternator belt is good. I replaced it last year, it's still tight, and the alternator spins merrily when engine is on.
-Cleaned and reseated battery connections. Wires are okay.
-With engine off, negative cable disconnected, I can put a test light between negative post on battery and negative cable and get nothing, so there isn't a short anywhere.
-With engine on, I read ~11.7V across the battery at idle and at a couple thousand rpm. With electrical accessories on, voltage is near the same, ~11.5V.
According to Bentley, that last point indicates the problem PROBABLY lies in the regulator. To be clear, Bentley says that if you check voltage across the battery with accessories off and compare that with accessories ON, and the result is about the same, it's probably the regulater, whereas if the voltage is LOWER with all the accessories on, it's probably the alternator. Question is, what exactly does Bentley mean by "lower"? How much of a difference would I be seeing? My headlights are on all the time, and my stereo was recently stolen, so really the only accessories I can turn on and off are my blower fan and rear-window defrost.
I've read other info that says 90% of "alternator" issues are fixed by replacing the regulator. I do hope it IS the regulator, because I can't afford another alternator right now. Is it fairly safe for me to point the finger at the regulator and install a new one as my first step? It looks pretty simple...any pitfalls waiting for me?
Thanks in advance!