testing alternator diodes shows zero both ways on mm but alternator charging at 14.6 volts dont no if i need a new alternator or not.not getting any ac to batt.any advice please

 

If it's charging at 14.6, that is correct.

 

ok thanks what ive got going on is my truck set for a month and the batt goes dead.its a new batt.i took off the neg cable and put test light between cable and neg post and it lights up.then i used mm from cable to neg post and showed almost same voltage as batt.expecting a batt drain i checked all fuses with mm found no drain.kind of at a loss i unhook the batt and it dont drain thats why i was looking at the alternator

 

Something is staying on that shouldn't. Usually its something silly like the underhood light, or glovebox light, or even the ashtray light..... something switched that a switch has failed. Put your meter on amps, disconnect positive battery terminal, and put the meter between the terminal, and cable. See how many amp draw you are getting there, with everything off.

 

ok i checked its drawing 1 amp

 

My 04 had a draw issue. Alternator tested fine. A drain test showed a draw no matter what fuse I pulled. Truck would start fine but if it sat more than a day it would die. I ended up finding a tracker in the dash right behind the e-brake release lever. Removed it and re-spliced the ignition wire it was cut into. No more parasitic draw and my truck can sit for weeks on end and start like it should. Inside the tracker was an old old Nokia phone from the early 00's. I think its battery finally took a dump and it kept drawing on the truck to try to charge itself.

Any chance you might have something like that hidden somewhere? Otherwise like HeyYou mentioned i'd check the underhood light and stuff that might not be turning off.

 

thanks for the help i found the problem glovebox light