electrical wizards ???

[oldS10dude]

My 96 crapped its alternator ... replaced it with new.... battery crapped right behind the alternator ... replaced it with new ... problem is this ... somewhere in the electrical harness maze is a relay or fuse that tells the alternator to start charging the battery .... I've checked voltages at all the fusible links and every other connection thats tied into the charging system .... BUT the one I can't find ..
I do not have a diagram of the charging system that is worthy of the paper its printed on for my truck ..really would like some input on this one ...

anybody ?? TIA for your help ...

[ILOUTFITTER]

What engine? 4.3?

[dt4ts3]

So the Alt is putting out juice and it's not getting to the battery? Or is it not putting out any voltage? Wires? It's probably some little known ground wire like in the abs or something... J/K

[ILOUTFITTER]

This might help

http://www.autozone.com/images/cds/gif/large/0900823d8018c179.gif

[oldS10dude]

ILOUTFITTER (http://www.s10planet.com/forum/member.php?u=7841) the truck is a 1996 S10 ZR2 4.3L

and (http://www.s10planet.com/forum/member.php?u=7841) ,I have that diagram... thanks

dt4ts3, (http://www.s10planet.com/forum/member.php?u=7693)
the way it was explained to me,was the alternator gets its signal through a circuit that says send juice to the battery when the battery voltage reaches a certain predetermined point.... my alternator is not getting that signal so its just sitting there idly spinning,while my battery is running all of the electrics until it dies ...

[bespurcell]

Wish I could help. I have a friend with an older Corvette that has the same prob. I haven't talked to him about it lately to see if he got it fixed.

[Zygoat]

going off of mine it should be the one wire weather pack connector that hooks to the alt. mines a 97 so i imagine they are the same. i left mine un hooked after i moved the batt to the back, and it did the same thing. so fallow that wire until u find the F*** up. i don't have my truck here but could check what it is supposed to be maybe this weekend (if you cant find the specs)

[franckybosnie]

I think I have the same problem here .... Bought the car last week , alternator voltage was fine on check up .... I was plugging my radio ... so few interior light were open ..... car stalled .... can't crank now ... batterie too low ...BUT everything else work??!! Normally when the battery is dead ... interior lights are very low ?? well ...I think it could be the same problem .... I'll read the answers :p

[C4Tom]

Bad battery cable or weak connection on starter? We used to check the alternator by disconnecting the positive side of the battery while it was running, if it dies your alternator is bad or the charge wire is bad/broken. Make sure there's a good ground too... corrosion can kill that connection.

[Mikz86TA]

OK. So you had an alt go bad. The alt charges the battery. So if your alt dies and you run on battery, then you end up deep-cycleing the battery. That will kill dells inside the battery.
You 1st need to verify the rest voltage of the battery. Should be 12.8v-13.5v if its strong. Start the truck and observe the voltage. Should be near 14.4v if the alt is doing its job at idle.
Be sure to put the meters leads on the battery post themselves. If there is any lower values in volts, then put the leads on the terminals and see if theres any change. Its not uncommon to have a bad battery terminal.
Check volts with multiple ground sources (block, alt mount, frame,chassis, neg cable mount)
Also check the positive side at multiple places (alt lug,battery post, battery terminal)
Check fuses too. Use a meter on continuity and check across the fuse ends is the best way.

[franckybosnie]

Ok .... that's weird ..... When I was installing my radio ... the fuse #4 blew .... I didn't pay attention , the cluster lights went out avt the voltmeter also ... well , not a big deal .... then ...10 minutes later , my car stopped ....dead battery ... I boosted my 96 jimmy 4.3 with my second car ... It acted like the alternator wasn't charging ... replaced the fuse ..... then it worked .... I checked the voltage .... without the fuse #4 = 12 volts .... WITH the fuse #4 = 13,06 volts .... is it normal? took many readings in a few spots .... always the same reading ....


OLDS10DUDE ...... maybe this can help you ...

[oldS10dude]

All good answers fellas .... I've done it all,volt metered until I'm volt metered out ... cleaned terminal ends on everything related to the start / charge system ... the battery volts are good ... the alternator is good ... leads have all been cleaned and tightened ... all fuses that I know about have been checked... and rechecked .... all fusible links have been checked for continuity... connectors have been disconnected ..pins checked ... and reconnected .....

I think there is a relay or mega fuse somewhere that I don't know about

I swear to you all when I find the culprit I will post it here for the planet to see and remember... I will even post a picture of the location of said offending part

[Zygoat]

i think you might want to try a new alt, there is alot of internal circuitry that regulates its output and it could be bad somewhere, worth a try at this point.

[C4Tom]

Did you have the battery load tested? Some can show a good voltage and yet drop a cell on load, which could also interrupt the charge cycle.

[Mikz86TA]

X2 on the load test. Most autoparts stores do it for free.
X2 on the alt test with load as well.

Im confident I could diagnose your issue if I was there...but its hard to do that over the net. I can only give you leads and insteuctions.

[Mikz86TA]

Not nessesarily. Lights will only be dim if the voltage is low. Which is usually below 10volts.
The cranking has moreso to do with amperage (current draw) than voltage.
The lamps and radio and other accesories are only drawing 15amps or less at max. Your starter can draw 50-100amps of current. Thats why most use a 'fusible link' and the battery is directly connected to the starter with that 4ga or bigger cable.

I think you need to retrace your steps. Sounds like you did a radio install. Probably had the door open and lamps on for a extended period of time and possible have an older battery in there to begin with.
Also I would like to know if you connected the radio (I assume its an aftermarket replacement) with an adapter harness or you cut out the OEM harness and hardwired it?
If you hardwired it and its a late model GM product, you can refer to my 'sticky' in the Electronics Thread Section which I have posted the correct wire colors and their functions. I worry that you may have wired the constant and ignition backwards. Its not uncommon especially in GMs. Cause the aftermarket std wire harness uses a Yellow wire as the constant and some years GM had a Yellow wire as the Ignition. I think I have the same problem here .... Bought the car last week , alternator voltage was fine on check up .... I was plugging my radio ... so few interior light were open ..... car stalled .... can't crank now ... batterie too low ...BUT everything else work??!! Normally when the battery is dead ... interior lights are very low ?? well ...I think it could be the same problem .... I'll read the answers :p

[franckybosnie]

MILKZ86TA ... I did cut the wire and plug my radio ... I already had the haynes manual with the electric diagram for the radio thanks ....
Yes the door was open and the dome also ... but I found this thread :
http://www.carspace.com/guides/1996-Chevy-Blazer-Fuse-and-4WD-Indicator-Light-Switch-Repair
seems like when you blow the #4 fuse ... the alternator get bypassed , I don'T know how, and it doesn't charge the batterie . I tried ... and this is it .... with the fuse #4 removed .... only 12 volts on the battery .... then I put the fuse back .... 13,6 volts on idle ...... did it few times ... same result ;)

[Mikz86TA]

Hmm interesting. Guess I didnt investigate it far enough. I like to focus on the obvious 1st and then go into more depth. Ive done some 'duh' stuff myself B4. Happens

[oldS10dude]

:D:D:D:D:D:D:D:D:D:DWOO HOO YIPPEE KI AYE FOTHER MUCKERS

after I spent 270 bucks on an alternator,battery and new positive battery lead.... my freakin' ZR2 is back on the road

the problem was just a bad battery .... but first this

yes, I did put a new stereo unit in the truck ,but that was last summer,AND
yes, I did have the dash surround out to change my AC control panel

BUT I never touched the instrument cluster ....

y'all may or not know that the instrument cluster is "plugged in" to a circuit board ... well ,mine was loose,well the bolts that secure it were loose on the right side and apparently while taking the front panel off the dash it pulled the instrument cluster out of the plug in enough to cause my volt gauge to show less than 10 and made me think that my alternator was bad... this also killed my battery,hell it was 4 years old anyway...I would have liked to have kept the 145 for the alternator in my pocket,but thats water under the bridge and besides..MY TRUCK IS BACK ON THE ROAD BOYS AND GIRLS...

[dt4ts3]

Yay!

[bespurcell]

WOOO HOOO! Glad you got it figured out.

[C4Tom]

Yeeehaaaaa! Gratz!

[franckybosnie]

NICE :) I'm glad you got your truck back on the road :) I'm just sorry that you spent 270$ ... for a battery ;)