PDA

View Full Version : Alternator Wont Charge Battery


240codyluukk13
07-01-2020, 09:51 PM
Was hoping somebody could give some advice on a problem.
I got a stock ka24e with a brand new alternator and battery, both were tested. for some reason the alternator doesn't charge the battery. I checked the grounds coming from the back of the alternator and tried to ground the alternator casing to the negative terminal on the battery. I also cleaned the mounting bracket and the block were it bolts hoping for a better ground.

I read on another thread that the white/red wire behind the cluster could cause an issue but after I noticed that the battery light on the cluster would turn on and off quick when I turned the key from accessory to the on position and same thing when the key is turned backwards. When it is in the on position the light stays off. I never had this problem with the light before so I think that has something to do with it.
The previous owner had an alarm system that was clearly rigged together that I had taken out. I think a wire may be shorting on something.

If anyone has any advice/pictures on the wiring under the ignition I would greatly appreciate it, thanks!

S14rebuild
07-02-2020, 05:37 AM
First check the voltage coming off of the alternator stud. What do u get?

240codyluukk13
07-02-2020, 05:56 PM
I got a reading of .013 with the meter connected to the positive on the battery and negative on alternator stud.

FaLKoN240
07-02-2020, 05:58 PM
That doesn't sound right at all .013 Volts???

240codyluukk13
07-02-2020, 06:28 PM
Yeah definitely not. Gonna trace the wire back and see if there?s anything wrong with it.

S14rebuild
07-02-2020, 06:41 PM
Multimeter set to dc.. red lead from multimeter to + stud on alternator...black lead from multimeter to battery negative...

Whats the reading?

240codyluukk13
07-03-2020, 10:00 AM
ok I will check later today. I also heard of someone wiring the stud on the alternator straight to the cluster because of the battery light issue. I was thinking thats where my issue might be. Any thoughts on this?

S14rebuild
07-03-2020, 12:09 PM
ok I will check later today. I also heard of someone wiring the stud on the alternator straight to the cluster because of the battery light issue. I was thinking thats where my issue might be. Any thoughts on this?


Lets acually find whats wrong with ur car before you start ghetto wiring stuff....

But the choice is urs..ur car

240codyluukk13
07-04-2020, 11:29 AM
So I tested the stud on the alternator and got a reading of 11.6 volts.

S14rebuild
07-04-2020, 12:14 PM
Okay, next check the 2 pin connector... show be white wire and a white with red tracer.

White wire should have 12v power constant

White w red tracer should have 12volt power key/ running.

Check those.


Heres a link to the fsm. I found the alternator wiring in it for you to check.
http://tech.240sxone.com/fsm/

240codyluukk13
07-04-2020, 01:24 PM
So the white/red wire Had less then a volt running and the white had 12.7 so I?m thinking it?s definitely gotta the the white/red wire.

S14rebuild
07-04-2020, 01:34 PM
Correct..that wire is the trigger wire..pull up the fsm ull see that goes to the bulb in the cluster.

If u supply volts to that wire the alt will turn on and start charging

240codyluukk13
07-04-2020, 02:09 PM
Ok so I wired it from the alt to the cluster just to see if it worked and the alternator started working and charging right.

S14rebuild
07-04-2020, 02:27 PM
U can just wire it to a 12volt pos key on and it will work aswell, no need to run a crqzy long wire

240codyluukk13
07-05-2020, 09:47 AM
so I have the alternator charging and everything works but I still have the battery light turning on and off when I put it in the on position. I tried switching out the bulb and still the same problem. Any thoughts on what this could be?

S14rebuild
07-05-2020, 09:53 AM
Put what in the "on" position?

240codyluukk13
07-05-2020, 12:35 PM
Sorry I meant when the key is in the on position all the dash lights turn on except my oil and battery light. The battery light will blink once and then shuts off the others stay on

S14rebuild
07-05-2020, 02:02 PM
Sounds like a cluster issue.

Once the car is running, the light should stay off. Then while running disconnect the alt power wire, the battery light should come on...thats how normal operation works

S14rebuild
07-05-2020, 02:02 PM
If anything reffer to the wiring diagram link i posted

240codyluukk13
07-05-2020, 02:27 PM
Ok thanks a lot for the help I appreciate it👍👍