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Alternator problems ?

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Alternator problems ?

loren3 loren3
New User | Posts: 1 | Joined: 05/13
Posted: 05/22/13
09:13 PM

I jerked out a tree stump with my 02 avalanche yesterday. This morning the truck was not charging so I headed to the parts house to get a new alternator but on the way it started charging. An hour later it wasnt. So I washed the engine compartment to get ready to rip into it and bingo it started charging. But after it dried it quit charging. On the charger it sparks on the hot post like there is a short. Any ideas ?  

waynep712222 waynep712222
Enthusiast | Posts: 251 | Joined: 03/13
Posted: 05/22/13
11:21 PM

this is similar to your truck...

99Chevypu53singlebattery140ampalt Zps1f3c799c

earlier today on another forum .. an 02 C2500 owner had a similar issue...

check the connections at the back of the alternator.. 19

check the connections at the relay box 20

check the connectors at the terminal block on the core support next to the battery #3.

check the connection at the starter  #16  

check the connection at the positive battery post.. #4 and #21..

check the connections at the negative battery post #22 and the body ground connection #5

there are several wires at the bottom passenger side front of the block.. where the negative cable from the battery hooks to the block..  but there is also a ground cable from there to the frame rail..

if the battery is discharged.. and the charger is on when you hook it up.. it will spark..

the other forum member found the cable loose at the relay box #20..  

Dave632 Dave632
Addict | Posts: 2217 | Joined: 07/08
Posted: 05/23/13
03:39 PM

Wayne where do you find all those nice diagrams that you show?  

tuffnuff tuffnuff
Moderator | Posts: 7827 | Joined: 12/09
Posted: 05/23/13
08:23 PM

I'm curious too.,. please share your lil secret with us.

When The Flag Drops.,.


The Bull ***t Stops.,.

P. Engineer, Engine Builder