Electrical issue

[arfalberg]

85 Jetta TD w/5k on rebuilt engine.  I have a new battery and a new alternator but still no current is coming from the alternator.  how can i check the stater (i think that is the spelling) wire for proper functioning?? what else could the issue be?? help help!!

[regcheeseman]

The altenator requires a live feed to energise it's field coils before it will give any input.

With the ignition on, this should be present and about 1.1 Amp if I recall....

If it's not this problem, then you have a faulty alt.

[shwartzbewithyou]

How many wires have you got coming off of the alt?

[arfalberg]

i will check the blue wire for the amps

i have 3 wires to my alternator  the main power wire, the blue wire to tell it to work or rest,  and the w terminal wire for the tach.

would a slipping belt cause such an issue??

[jtanguay]

i will check the blue wire for the amps

i have 3 wires to my alternator  the main power wire, the blue wire to tell it to work or rest,  and the w terminal wire for the tach.

would a slipping belt cause such an issue??

yep... the alternator does put quite a load on the system, and the alt belt is prone to getting loose.  Tighten the belt, but not too tight or it will burn the pulley off your alternator (happened to me).

I recently fixed my a/c.  When turn it on, my rpm's die at idle every so often and I hear a nice squeal (belt slipping)  - a/c puts a huge load on the system, as well as the alternator.  Gotta fix that damn belt issue

[arfalberg]

i had to get a belt that was .5 inches shorter but now that belt is tight and i still got room to tighten it when it stretches. so the alt issue is fixed but please look at my new issue concerning my dash instuments. it all started after i got the alt fixed so i am wondering if it is related.

[shwartzbewithyou]

What issue is that?

Are you getting a battery light on the dash or is that fixed?  If not, their should be a wire going from the alt to the dash.  I believe there is the large red wire, a small blue wire and another small red wire if I'm correct.  Without the one connected to the dash the battery light will come on and the alt won't charge the battery.
I could go into detail of why but first let me know if I'm barking up the right tree.