Help alternator wont charge battery (searched)

[unwtdhero]

Alright, today i traded my s13 rb20 for a 89 hatch with redtop sr20det. He had just recently swapped the motor and could not figure it all out, he had the wiring done professionally for a 91 and up 240sx (due to the difference in the chassis harness). So heres the problem, and no i could not find a thread or post for it, i can drive it but only til the battery dies. Obviously the alternator isnt charging the battery, he mentioned re-pinning a plug. but i cant go by what he says cause quite frankly he doesnt know. but neither do i, so help please. I will return the favor with rep points, if valid replys.

thanks ahead of time.

[sikkk240]

Your rep wont do nothing..

Have you atleast checked the alt. ?

[unwtdhero]

Yes, i had it tested at autozone. im think its the plug that comes off the fuse box that connects to the lower harness and eventually to the alternator

[projectRDM]

There's only three connections on the alternator. Ground from the chassis, charging lead to the main fusebox, and the 2pin plug that powers the charge warning light and the turn on feed from the fusebox. It that's all connected and you have no blown fuses, the alternator is not charging. Easiest way to test it is to remove the charging lead and test voltage directly at the terminal on the back of the alternator with the engine running, anything below 12.4V is shit.

[unwtdhero]

Thanks R240NA, anymore ideas anyone?

[s13rookie]

Thanks R240NA, anymore ideas anyone?


nope,short of someone coming to your house to do it for you, r240na pretty much gave you your options

[unwtdhero]

Haha alright guys i really appreciate it

[GabeS14]

When I first got the sr swap, My car did the same thing, it would start after a jump then run till batt died.
It took me a while to realize that the end of the power line connected to the Alternator was really rusty with that greenish whiteish residue (battery acid looking)on the wire, after replacing that cable, it ran fine, simple ass problem, with simple fix, took hours to find the problem though, cuz the end of the wire was coved by a plastic boot, only when i disconnected it did i see the rust.