dead battery ....ect! i dont know

[box369]

hello, my wife was driving home from work in my truck (98 s-10 blazer) and it just died all the gauges went to zero and it quit. i jumped her four times to get the !@#$%# truck home. well i changed the alternator (stock)and battery(bosch) at the same time.

Now my gauges reads around 12 volts idle and around 14 while driving.....is this a problem

and how do i reset that annoying battery light or should it just go away when the problem is fixed?

my truck does idle a little slow though it idles at like 500rpms maybe thats normal but my wifes car is around 800rmps i work on air planes dont know a thing about cars though please help!

[marly87]

There has been several posts about this problem. It seems the recurring answer is the ignition module.

[old_master]

If the vehicle is running at approximately 1500 rpm with 12 volts showing on the guage, and the battery light is on, it is in fact telling you that the charging system is not working. Having to "jump her 4 times to get her home" tells me two things: #1 The battery is low and not being charged while driving. And, #2 uhh, we won't get into that one here.

When the system is operating correctly, it should indicate approximately 14 volts at 1500 RPM, all accessories turned off, and no "BATTERY" light on. There are two wires on the back of the alternator. The small one needs battery voltage any time the key is in the "RUN" position. With the key in the "RUN" position and the light on, unplug the small wire, if the light goes off, that circuit is ok. The small wire feeds the regulator circuit and turns the light off when the stator circuit in the alternator has output. The larger wire should have battery voltage all the time, key on or off. This is a 10awg wire and has a fuse link attached at the starter. This circuit charges the battery. The alternator needs a good, clean, tight ground connection, usually accomplished when bolting the alternator on the vehicle. Make these checks and report back here. Just because an alternator is new, doesn't necessarily mean it's good. If you have battery voltage at those two places, a good ground, and still no output, you have a bad alternator.

[mike2004tct]

You should have a minimum 13.5V at idle.
Sounds like a bad alternator to me, but before you get another one, check your belt to make sure it's tight. You might have a bad belt tensioner. Or possibly just a bad belt (is it worn on the pully contact side?)

[BlazerLT]

Yip, dead short somewhere.

I would have a shop check it out.

Could be a failed battery.