Replaced Alternator but battery light is still on.

[GypsyRose]

Hey guys So here is the scoop. My alternator failed in my 98 4runner on me the other day. I just replaced it with a used but working alternator from my 97 4runner. After I installed the new one I noticed the battery light is still on, is this something that will shut off on its own after driving a bit maybe? Or is there something that could be causing it to stay on? I checked all the wires and they seem to be installed right. Could an alternator from a 97 not be interchangeable with a 98?

I also unhooked to battery with the truck running to see if it would still run off just the alternator and it did just fine( I know I know, its a no no).

Any help would be appreciated

 

[EraSevera]

Get that battery load tested.

 

[Skidmarcx]

Did you verify that's it's working with a DVOM? By chance did the fuse pop?

 

[EatonKyleH]

Hey guys So here is the scoop. My alternator failed in my 98 4runner on me the other day. I just replaced it with a used but working alternator from my 97 4runner. After I installed the new one I noticed the battery light is still on, is this something that will shut off on its own after driving a bit maybe? Or is there something that could be causing it to stay on? I checked all the wires and they seem to be installed right. Could an alternator from a 97 not be interchangeable with a 98?

I also unhooked to battery with the truck running to see if it would still run off just the alternator and it did just fine( I know I know, its a no no).

Any help would be appreciated

Monitor the voltage to all three wires with the connector disconnected, key on. All three wires should have 12v disconnected, plugged in and engine running.

On several occasions I've seen the wire for the battery light broken in the loom... typically near where it plugs into the alternator. Anyway, the above test will let you know if that is also the case on yours.

 

[LittleCaesar]

Verify with a DVM that you have at least 13.4~13.5 volts at the battery, 4runner running. Kyle's test(s) should find you the culprit.