Hi,
Since I've had my Bug, the generator light has been steady on. The wiring harness is a nightmare and since the battery has been getting charged....simpler just to not get involved. It's always made me nervous though, and sure enough I recently had the belt come off due to an under-tight alternator pulley nut. The engine overheated before I realized anything was wrong, though thankfully it was just around town and not on the highway where some serious damage would have been done.
Realizing the error of my ways, I set out to fix that damn light. The car (a '74 standard) has had an alternator conversion, but whoever did it used some creative wiring. At the alternator, there is a large red/ white [1] AND a mysterious black wire [2] connected to the B+ terminal, and a mysterious red wire [3] connected to the D+ terminal. I tried connecting the hacked-off remains of the green wire to the alternator, but it did nothing.
Today I started monkeying with it some more and only after finding Speedy Jim's pages on the subject (highly informative, kudos to Jim) did things finally make sense. So, I spliced the blue and green wires from the regulator together and replaced the mysterious red wire on the D+ terminal with the green wire. Unfortunately, the light STILL doesn't work as it should.
I am fairly certain it is wired correctly, and the light does come on with the key, but stays on while the engine is running (however, its brightness is now directly related to engine speed, whereas before it was inversely related). I believe the problem is that with ignition on and engine not running, the voltage at the green wire is a measly
9-10 volts. The D+ terminal puts out 14-15 volts when running. I figure the wiring on the ignition side of the light is just so shoddy that there is enough "backflow" though the warning light to keep it on. The voltage at the red wire (that was previously connected to D+) is more like 11-12 volts, still not equal to the battery voltage but closer. Now that I'm thinking about it, I'm not even sure how the warning light was working before, as the blue wire wasn't connected to anything before I started...So, anyway, does anybody think I have a chance at getting this working without rewiring the entire car? I fully intend to do that, and soon, but it would be nice to have the light working in the meanwhile. Also, I figure it probably isn't good for the alternator to be seeing that low of a voltage at the D+ terminal. Would I be better off just using the mysterious red wire until I rewire the whole damn thing and put these issues behind me?
Thanks, Harry
[1] The red/white wire appears to be correctly spliced into the battery and fusebox. [2] I have no clue where this goes. [3] No clue where this goes either, though it does not appear to be the red wire that used to go to the regulator, as that looks undisturbed under the rear seat.