how come my van won't charge, after replacing altornater and battery. on 1996 GMC Savana 2500

My alternator was getting weak, but before i could change it, i went to go to work, and after starting and turning on head lights i saw alternator gage fall. put it back in garage and changed alternator and battery and now refuses to charge. checked all connections and seems to fine. HAD NEW ALTERNATOR TESTED BEFOR INSTALL, DUE TO THE FUN JOB OF WORKING ON A VAN. could it be something from the small wire clip and where do these wires run to and what for. THANKS FOR ANYONES HELP, Sinserly Rich

by in Cincinnati, OH on December 11, 2012
4 answers 7 comments
ANSWER by on December 11, 2012
maybe the wires are not connected good
COMMENT by on December 12, 2012
I checked them
ANSWER by on December 11, 2012
Where did you get the replacment alternator? Is the battery new and fully charged? 12 volts @ big wire on back of alt.? Who tested alt.? What is voltage at the battery with engine running?
COMMENT by on December 12, 2012
o'reily's , yes , yes , o'reily's , starts at 12 and goes down.
ANSWER by on December 11, 2012
I agree with wetry I would first check for power going to the alt
COMMENT by on December 12, 2012
thanks for your help.
ANSWER by on December 11, 2012
Do you have 12V going to the alternator when not running? no=wiring problem; yes=charging problem, maybe you missed a wire or your alternator is BAD!
COMMENT by on December 12, 2012
Going to pull it and get another one and try it. Thanks to all thats helping. This afternoon before tearing everything apart, I reconnected battery and hit the key, and beleive it or not it started charging!!!!!!!!!! I'm thinking it had something to do with the computer and with it not having voltage for a good period it started letting it charge. Any answers to that, cause I don't know. THANKS AGAIN
COMMENT by on December 13, 2012
Alt. brushes may have not been seated, now they are.
COMMENT by on December 14, 2012
never thoght of that , thanks
COMMENT by on December 14, 2012
See it from time to time on GM. It should be ok now.