MS3 Gold box Alt Field wire

[jon volk]

I have a plug and play LS1 harness and noticed my alternator wasn't charging. When I hooked up the multimeter, I was expecting to see somewhere between 5 and 12 volts at the alternator field wire. There was nothing. I jumped a 12v ign wire to this pin on the alternator and it started charging. Should I be seeing voltage at this wire, and if so, do I need to set up the alternator control in the software to initiate this? Currently the alternator control is off. Any LS1 base tune Ive seen for this ecu has it off as well.

Any input?

[jon volk]

Actually, I think I may have it figured out. Im going to try setting it to on/off with JS11 as the control and go from there. If that is incorrect, someone please chime in.

[jsmcortina]

Many LS1 alternators are an on/off type only. There isn't a great deal to be gained from trying to control these from the ECU, so wiring up a charge light in the conventional way is probably best.

James

[jhkm12345]

can you confirm the "on/off with JS11 as the control" worked?

I was trying the same thing but got a power cycling in the ecu when it was hooked up. from pin 12/alt in the black plug housing to the field / lamp terminal on the alternator. Confirmed the alternator field with a jumper and bulb... charges perfectly.