Tack just stopped working

[91jettaidi]

Hey guys my tach stopped working one day and when ever i drive in the rain it some times works but i hear a squeal(like a belt)but i don't know what it is.

[rallydiesel]

Sounds like you have a problem at the w terminal on your alternator. Be careful if it is loose because you could blow a bunch of stuff. My w terminal shorted against the alternator housing and blew my radio fuse, wrecked my tach and junked my alternator. Not fun.

[91jettaidi]

so i should just tighten all the wires on my alternator

[Vincent Waldon]

As well, loose alternator belt = slips when wet = makes a squealing noise = wonky tach operation.

[91jettaidi]

ya i tightened my belt but. . .it seems only in the rain it wanted to work some times but where is that terminal on the alternator? should i take it out and clean it a bit? and retighten it.

[rallydiesel]

There will be one wire going into the alternator with a quick connect joint. That is the w terminal which is what your tach uses to determine rpm. There is really no way to tighten it. Just make sure it is not contacting the actual  alternator housing. That's just one possibility of why your tach isn't working.