My 2000 ZR2 Blazer will not Run with Battery Hooked Up
 

Hello I have a 2000 ZR2 Blazer A few Days ago i had my pulley lock up and blow my belt off the truck. I re-placed the pulley and new Belt. Then this morning i went to go to work jumped in my truck started it and the volt gauge reads 9V and then the truck wanted to die out turned truck off and called in about an alternator and changed the alternator and had to battery checked and everything was good. Hooked up the new Alternator and hook up the battery. started the truck same thing. UN hooked the battery and truck ran at 14V truck runs great without and battery but yet both Battery and Alternator are good. Anyone have any idea. And also tryed different battery and alternator.

Thanks GeeRacing.