So, I got a nifty VDO tach to be driven off the "W" terminal on my alternator, then after getting all set to install it, I find out I don't have a "W" plug. :cry:
Can I add one to it? Or if not, what alternator should I buy to get one. Thanks in advance.
Yes, you just need to hook a wire up to the alt from any of the phases before it goes through the diode. On a GM alt, you can use a ring terminal on one of the studs. I'm not sure how the diodes are in a normal VW alt though. Just make sure the wire won't get caught on anything rotating and that it is well insulated.
also make it as flimsy as possible, so that it fuses instantly if something goes wrong.