Hi all,

I bought this Brat 8 years ago, already swapped.  A couple of months ago, I found a dead battery.  I charged it, Brat started right up.  Battery that came with the Brat, so at least 8 years old.  In the process, I checked and found the alternator not charging. New alternator, also not charging. Returned new alternator.  Took original alternator to shop. Found out exciter is not getting voltage to start charging.  I have now replaced the battery, still not charging from alternator.  I have a 3 wire plug in the top of the alternator. Thick white wire is 12.10V. Yellow wire, 0v. Black wire red tracer, 0V. 
I think white wire is battery voltage and Yellow wire is 12v switched.  Not sure on the black/red wire.  I can “force” the alternator to charge by jumping battery to white wire pin and a 12v switched source. 
I have seen a few threads about a battery light in the dash being in one of the small lines.  Gauges and lights attached in the dash have never worked. All fuses are good.  I would like to run the original wiring if possible.  Anyone know what the yellow and black wires go to in a swapped Brat?  Do they splice into the Brat harness or stay separate?

The wire to the charge light must be connected through that bulb (or a comparable resistor) to a switched power source to excite the alternator.

15 hours ago, Numbchux said:

The wire to the charge light must be connected through that bulb (or a comparable resistor) to a switched power source to excite the alternator.

^ this! 100% the issue. Once done it’ll work perfect. 

Cheers 

Bennie

Yellow wire or black wire red stripe?   Not looking forward to pulling gauge panel. Pretty rough as it is.