I really need help

my altinator in my 1990 FC keeps going out. this is the second one i have put in there. the regulator on it keeps getting messed up and the battery gets over charged. whats causing it

 

the most common reasons for a regulator failing is that it is either wired wrong, or having to charge too much and overheating.

Do you have a high power stereo system or bad battery?

If it is not the regulator, then check your belt tension. Common for people to overtighten the alt belts and distroy the bearings leading to early alt failure.

 

well i dont have a high powered sterreo all i have is a new head. but would a bad battery cause it

 

what is the voltage with the radio on...

The voltage should never drop under 13.5 volts... running too long under 13.5 volts will overheat the regulator, and could cause the overcharge situation.

If the alt is consistently over 15 volts as soon as you plug it in, then I would be looking at a wiring issue to the alt.

Of course crappy rebuilt alts could cause the same problem. Make sure you are buying Remanufactured or new alts... not rebuilt.

 

Yeah its a brandnew one.

its got a warrenty on it so i dont have to pay for it
and i bought a new battery so well see if that helps and if that dosnt help then its deff a wiring issue

 

Not too many people pay the $200+ that a brand new alt costs from Mazda... are you sure it's not just a rebuilt one from the local parts store???

and you still have not posted what the voltages are.