motor is in, and runs, but gen light is on

[hondarider290]

Well if you've read any of my earlier posts you will know that I'm working on my first ever beetle and trying like hell to get it ready to drive. It ran good before I had to pull the motor for the stripped spark plug but now the generator light is staying on. It alway came on before but went out as soon as the car was started. Now this isn't the case. I've read up on some things it could be but what should I check first? thanx again for any help, I"m much farther along than I would be if it weren't for you guys and this site...

[turboblue]

Polarize it.
http://www.vw-resource.com/alternator_g ... html#polar

[Marc]

I just looked at one of your pictures and noticed your generator has the plastic cover over the top brush - you'll need to lift that off to inspect the upper brush, the lower one is sorta visible (a mirror helps). They should both be standing taller than the metal holder that surrounds them, if they're worn below that there won't be enough spring tension to hold them in good contact with the commutator. If they are worn down, you can usually confirm that new ones will fix it by pressing in on the brushes with the engine running at a brisk idle (be careful doing this, and don't wear long sleeves that could get caught in the belt). If the brushes aren't bouncing, the commutator's still round...the warning light should go out too.

[hondarider290]

tried pressing on the brushes and well, it didn't work at all, should i try new ones? and should it be sparking or anything?

[Marc]

Do the polarization procedure. Basically you're just motorizing the generator when you do this - and if it won't work as a motor, it won't work as a generator either.

[hondarider290]

Ok will try to polarize it...but got a question and it may be a bit dumb lol, it says that when I polarize it I need to run a jumper from the battery positive, can I remove the battery to do this or do I need a long jumper wire coming from the battery while its in the back seat?

[Marc]

The battery could be sitting on the ground behind the car...note that you'll have to run a wire from its negative post to the engine in order for there to be a complete circuit, so it's your choice - one long wire or two shorter ones.

[hondarider290]

Tried to polarize the generator but it didn't work, the generator would kick just a little but it wouldn't spin...do I just need a new generator and if so which one? Mine seems to look like the pictures I see of the Bosch generators but how do I know for sure? And is there any way I can figure out the year of my motor so when I order parts it will be for the correct year...

[Marc]

Look at the generator housing near the fan end, you should find "14V" and "30A" stamped into it. 99.9% of 12V generators used on VWs are this model, known as GR15. Early ones (`67-mid`69) came with push-on terminals, all since have studs for ring terminals.
It's not common to find a Bosch rebuilt (GR15X) anymore, but new ones (GR15N) from Bosch Brazil are available for ~$150:
http://www.actionimport.com/
There are also Chinese counterfeits made that go for ~$30 less, I can't tell you if they're worth trying. Reports on Chinese-made alternators indicate that it's hit-or-miss (if they last a week they'll probably last for years).
It'd be wise to install a new voltage regulator (0 190 350 068 is one of the modern electronic models that'll work) - that's another ~$30.
http://www.cip1.com/

Now would be the time to update to an alternator, if you've considered it. New Bosch AL82N go for ~$200, and Chinese are ~$120 (they're internally regulated so there's no additional cost for a regulator). There are potential problems with the carb accelerator pump linkage clearing the alternator housing (may need to space the carb up and/or grind a bit on the housing with most singleport carbs; dualport 34PICT-3 carbs may need the linkage replaced with redesigned "alternator" bits). The pedestal has to be replaced, counterfeits are available for ~$15 or you may be able to find a good used one. The pulley, sheetmetal, fan, strap, etc. from a 12V generator will all fit so there's no need to purchase a "kit" - those are for people changing up from 6V. Some very simple wiring modifications are needed. Result is higher output (50-55A).