I am replacing the alternator on my 99 z28 and I see that there is a ground wire on the back held on with a 13mm nut and there is a connector with ONLY ONE wire going into it. I thought maybe the wires had been cut or pulled out but upon further inspection I cant find any other wires and also there are no connector pins inside the connector other than the one wire. Can someone please enlighten me because I'm a little confused. Thank You

 

No there is only supposed to be one wire. I believe it is called the exciter wire, when I removed my alternator once I tore the wire out of the connector.

 

Yep .... same thing that I found on my '99 Z28. I had to replace the pigtail that connects to the altenator.

 

If your alternator ONLY has a ground and the battery connector wires then someone may have replaced the alternator with a 'single-wire' replacement that does not use the multi-pin exciter and voltage sense wires common to most all OEM alternators.

 

The wire on the back is not a ground wire (it is positive), and the wire on top is an exciter/field wire. These should be the only two wires connected to a stock alternator on your '99 Z28.

 

One-wire alternators are just that; one wire only. If that was the case here, it wouldn't have two wires.

One-wire units are "excited" by rpm rather than battery voltage. They only require one wire, and that wire is used for charge output (not ground, not exciter).