ok well my alternator is doin 12 volts normally with 13.4 the highest. but some times it just goes to 8.5 volts for no reason, with no rpm change. also all my lights and crap dim. is my belt on too tight, too loose? whats normal voltage. thanks for the help!

 

OK same thing just and i mean just happened to me, GET A NEW OR REBUILT ALT QUICK mine left me stranded for 2 hours after it fell below 8volts, so listen to me and an alt takes about 1 min to install just make sure belt is very tight!

 

Alternator is dieing. Replace

 

Try tightening your belt first.. I believe Mazda recommends there be a thumb width of movement when you press on the side of the belt.

 

oh yeh i replaced the alternator 5 days ago. my old one was destroying my electrical, it was doing a nice old 19 volts.