Bad Alternator?
 

My 97 Montero has a new problem with at low RPMS and with the headlights on it makes the voltage meter go down below 12 and the A/T, Brake and Check battery light come on. I tried a new battery and it did the same thing so I am guessing the Alternator. Does it have the voltage regulator built into the alt? Thanks in advance.

-James

RE: Bad Alternator?
 

Yes, the regulator is built into the alternator. You should have at least 14v at all times when the engine is running. If not, check the alternator fuse before condemning the alternator.

JJ

RE: Bad Alternator?
 

Same thing happened to my '98. Had to have the Alt. rebuilt. After 3 times of R&Rthe rebuild shopFINALLY replaced the 'diode' assembly and all is well. When it got 'hot' after justa few minutes of running, the lights would comeon and you could watch the volt meterstart dropping.

RE: Bad Alternator?
 

Check the grounds and the alt output.

RE: Bad Alternator?
 

Well I ended up getting the alt rebuilt and that did the trick. Thanks guys!

Thanks guys for all you're knowledge. I went ahead and pulled the 3 day old OEM alternator and new idler pulley out of the crashed 96. It was a bear to get it out as my son hit the tree on the right front behind the wheel and into the A pillar. It distorted the right inner fender where the air cleaner assembly is bolted on. Everything seems to be "A" OK.

Thanks again, I'm sure I'll have more questions.