Mechanics

CHEVY ALTERNATOR TEST

1997 Chevrolet S-10

Electrical problem
1997 Chevy S-10 4 cyl Two Wheel Drive Manual

So I performed the " backyard" alternator test by starting up my truck followed by pulling the negative battery cable. It continued to idle after the disconnection, however, I turned the headlights on and the engine stalled. Should that have happened or should the alternator be able to run the truck and headlights while still providing some extra to charge the battery? My main problem is my battery is dead only on the mornings after i've driven my truck with the headlights on. Any thoughts or suggestion?
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Ericde
April 25, 2010.




Do a battery drain test

Battery drained in the AM only its not an alternator and most likely something is draining the battery over night

BMRFIXIT
Apr 25, 2010.
Thank you for the suggestion I just checked out the section on testing a battery and will be trying that right now.

Tiny
Ericde
Apr 25, 2010.
Good luck
let me know

BMRFIXIT
Apr 25, 2010.
So using a multimeter I did a surface voltage check, 12.73. Now when I connect the meter between the negative cable and the negative terminal it reads the same, did I do the test right?

Tiny
Ericde
Apr 25, 2010.
Also you can use a test light to connect the same way and watch the light to go dimmer as you pull the fuses and look for what is causing the drain
Start pulling fuses make sure that the door is closed and or the door switch is off
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BMRFIXIT
Apr 25, 2010.
I set up a test light and began pulling fuses but the light never dimmed. I traced the negative cable to the engine block and didn't see any corrosion. I've been disconnecting the ground while parked for a few weeks now and had the time today to try figuring it out. Would a full draw or bright test light mean that its grounded out somewhere?

Tiny
Ericde
Apr 25, 2010.
Bad ground will not cause a draw
Defective radio would if have an electrical door locks, stuck actuator would light on in the trunk would defective diode in the alternator would
The reason for the battery is draining something is staying on
Have to locate and find
Key off and all accessories off
If need to access the inside of the car make sure door switch off and not turning the inertial lights on Light should dim when to almost go out when no more draw and pulling fuses is to locate that circuit

BMRFIXIT
Apr 26, 2010.
Just wanted to say thanks, I narrowed it down to the Number 3 fuse, now to figure out what all is on that circuit and fix it.

Tiny
Ericde
Apr 26, 2010.


http://www.2carpros.com/forum/automotive_pictures/99387_7830a_thumbnail_3.jpg


BMRFIXIT
Apr 27, 2010.
So I found a wiring diagram for that fuse, the first thing in line was the under hood lamp, with the test light on, a slight wiggle of the lamp caused the test light to flicker, so I unplugged the bulb and the test light dimmed. So i'll leave it unplugged till I can get the mercury switch replaced. Im having a hard time finding information on how much draw the truck should have on the battery while the key is off, right now it measures 3.30v that still sounds high to me but I really have no clue.

Tiny
Ericde
Apr 27, 2010.

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