Replace my alternator... again?

[swardan]

1998 Merc Mountaineer – I replaced the alternator about 100 miles ago – but 6 months ago – the poor thing has been sitting. Fired it up this weekend, and it is only pushing 9 volts. Before I spend the $$$ on another alternator, I wanted to see if there is something else that could be causing problems.

Does anybody have any thoughts?

Thanks!

 

[budwich]

Well.... you need to check a few things like..... your battery voltage..... if its low (likely), try putting a charger on it for a day. After that, the voltage should come up to "normal" .... somewhere around 12-13 volts..... if it doesn,t, then it is likely you have a dead cell or two and you aren't helping your alternator in this mode. If the voltage does come up, then try starting and measuring your voltage thereafter (ie. running).... should not be 13-14 volts. If it is lower, then maybe you have an alternator problem but more likely a cable or connector problem. Make sure that the connection on the alternator are clean and good.... same at the battery end. Lastly, you can usually get both your battery and alternator tested (benchwise) at most parts store. In addition, most alternators have a 1 years warrantee and it sounds like yours is only about 6 months old so maybe just take it back to your place of purchase.

 

[Green98XLT]

Ditto.. check that battery voltage. It should not be under 12.6V, if it is then it needs charged. If the battery is OK then start it up and check voltage at the back of the alternator- you should see at least 13 volts here. Now check it at the battery- should be no less than a .2v drop.