S13 RB25 Charging Issue

[whosawmike]

I'm finishing the RB25 NEO swap into my S13 Silvia and am hitting some issues. The engine runs strong until the battery dies (I made it about a mile into the test drive...)

The alternator is not charging and I think that the problem is in the wiring to the voltage regulator. In troubleshooting, I looked through the pinouts on wiringspecialties site. The charging light on the dash goes through the interface connector under the dash. If that connection is bad, will this cause an issue?

I am looking at that connector because on the test drive, the tach and speedo also did not work. They also go through that connector.

Can anyone give some direction into troubleshooting this?
Is the dash light integral to the charging in the RB25?

A wiring diagram in English would be swell.


Thanks everyone.

[blkvrtswp]

Yes you must have the alt light circuit in place or the alternator will not try to charge the battery. Hook it up or you can use a resistor if you are not running the stock cluster.

[whosawmike]

Originally Posted by blkvrtswp

Yes you must have the alt light circuit in place or the alternator will not try to charge the battery. Hook it up or you can use a resistor if you are not running the stock cluster.

Thank you! It is the stock s13 non digital cluster. Also, the temp and fuel gauges appear to work.

Do you know if the warning light gets power from one of the powers in the interface connector? Maybe H in the pinout I attached?

I'm wondering if the tach and speedo are related... Maybe they are all powered by the same pin.

I'm not at home right now, so I am just trying to get by troubleshooting ducks in a row. I'd like to get this licked tonight.

[whosawmike]

I am still scratching my head about this. Please send help!

In my original post I seem to have been off with the wiring. I traced the wire from the alternator and see that it does not use the connector I referenced at all.

Here is what I have got:
I have constant battery power at the one pin on the alternator
I have battery power with ignition at the other.
No light on the dash with ignition, but I can jump it at the alternator and it will light up.

I removed the alternator and took it to oriley. It passed the bench test, but I'm not sure I trust them...

Can anyone explain to me the switched ignition circuit for the excitation wire? I still feel like that is my issue.

Is there a way to "hard wire" the 2 pins on the alternator to bypass the harness?

Thanks!

[dalecl9]

Im having the exact same issue and still havent came up with a solution

[whosawmike]

Originally Posted by dalecl9

Im having the exact same issue and still havent came up with a solution

My issue turned out to be a loose connection on the 2 pin on the alternator.

While I was troubleshooting, I had the key on and was messing with the alternator. I touched that 2 pin and heard a click. Looked at the dash and the battery light was on. When I wiggled the connector, I could hear it clicking on and off. It was a simple fix, but finding the issue was a pain.