I had a run in with a bad alternator, I learned a couple of things that might help ya Options

[DNHunt]

The car didn't quite seem right. The starter seemed weak, the lights rose slower, and the fuel level on the gauge wasn't steady. The voltmeter was saying about 11 volts but, who believes the ones in the console (there supposed to be a piece of Sh*t). After a couple of days of wondering and scratching my head I came to the conclusion something wasn't right. Guess what, the voltmeter was right, my battery wasn't charging and the warning light wasn't coming on at all even with the engine not running.

After some thought and an hour looking at the wiring diagram I decided the bulb in the dash was bad so I switch it with another one. It was OK, damn more head scratching and looking at the diagram. I checked fuse 9 even though I knew other stuff on it was OK. Sure enough it was fine. Now I'm beginning to get a bad feeling. I'm hoping it's the voltage regulator but, I really don't want to buy one yet so I go back to the wiring diagram. If I had to suffer so do you, take good look



K2 is the alternator warning light. It gets 12V from the hot side of fuse 9. It grounds through the alternator. When you turn on the key and the engine is not running or the fan belt is broken and the alternator isn't turning, the light comes on. So to check that circuit I turned on the ignition and ran a jumper to ground from the D+ pin of the 3 pin connector for the voltage regulator on the relay board and the light came on. So my circuit was good back to the voltage regulator.

Next, I got out the digital volt meter. I tested the voltage at the plug for the alternator harness, pin D+ again, the red wire. 9.71 V is what I got so I really scratched my head. If I want the alternator light to come on this should read 0 or darn close. Ah the diagram shows diodes in the alternator and some are pointing toward the battery. I'm no electronics wizard but, I know diodes are like check valves in plumbing, they should only let current flow 1 direction and these should be keeping current from flowing toward the alternator warning light so something is kaput. I am pretty sure my alternator diodes are shot so I plunked down the money for a rebuild and figure I got a big job Friday PM. The good news is uder my car is still really clean.

It took an hour and a half to get it out, I got tools and crap all over the garage. I got the new one and took in the core and like a good boy I really inspected the 2. They look the same so off I got to what I assume is another hour and a half maybe less. WRONG!!

I was aware of the studs being too long so I whack off a chunk of each and try on the back. It doesn't fit. WTF (IMG:style_emoticons/default/headbang.gif) Much head scratch and a few choice comments I'll have to explain in the bye and bye. Guess what? The plate for the diodes is above the level of the rim of the alternator and it interferes with the flat area on the back plate. More choice words, my interview with St. Peter is getting longer. So, I got out a core to have a look. The areas in the white circles interfere.





So, I take apart the core to see what is under that plate. I can fix that I'll exchange the insulated washers cause the new ones are really thick and they stuck a couple of washers in there to that i can take out. That will lower the plate. See in the white circle.





Ah, but there is a problem, there is no backing nut on the stud cause that would conduct to case and short stuff so I lost something inside the core alternator but, I know to be really careful with the new one. I get it back together and it's still to high. (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif) (IMG:style_emoticons/default/headbang.gif) So, I take it back apart and am really careful with the studs. I use the bench grinder to thin the nuts down and retap them. Finally I got it back together and there was clearance. Wasted time = 2 hours. Another hour and a half and it works fine.

The moral, watch the studs for height but, check the alternator at the shop to make sure that the black plate is recessed into the body of the alternator or itis going to short out.