1981 Gmc Electrical Issues

[brady0666]

i have a 1981 gmc sierra shortbox half ton, we were removing the alternator when the alternator dropped and touched the heads creating an arc against the battery side wire on the alternator. we put the alternator back in and the truck does not have any power now, so we replaced the alternator with a remanufactured one from gm and the truck will still not turn over, however if you jump the incoming power wire to the battery out wire it will turn over and start, i am very frustrated as we have just spent months restoring this truck and something as stupid as this is holding me back from driving it, your help would be greatly appreciated

[bill190]

I don't understand what you are jumping...

 

But main battery wires have "fusible links" in them, so if shorted, the wire itself will "go bad".

 

So check your main wires while disconnected at one end with an ohm meter to see if there still is continuity.

[brady0666]

I don't understand what you are jumping...

 

But main battery wires have "fusible links" in them, so if shorted, the wire itself will "go bad".

 

So check your main wires while disconnected at one end with an ohm meter to see if there still is continuity.

 

on your alternator there are 2 wires coming in, ones black and ones red and on the backside there is a single wire that is red that is going out that charge the battery, if you jump your red wire coming in to your red wire out to complete the circut it will turn over and start, i hope that is more clear

[brady0666]

no worries i fixed it already, there was a melted wire in the wiring harness, but shes all fixed now

[bill190]

Be aware that the wire which was "melted" was probably a fusible link wire!

 

This is a fuse which is a part of the wire. The correct way to repair this is to get a new fusible link wire from the dealer.

 

If you just replace it with regular wire, it will not longer have fuse protection.