Battery light 01 tacoma

I'd use a digital multimeter on the generator bat terminal, check voltage different rpms. Usually I want the charging system voltage to be over 13 volts with all accessories on, if possible. The way I understand charge indicator lamp circuits, with engine running, voltage on both circuits, no ground, w/o a ground the lamp can't come on, unless problem with instrument cluster or wiring circuits--generator. If the charging system out-put is good at different rpms, I guess it's up to you if want to worry about the lamp. Just my opinion. I didn't see any computer control over your generator, in the wiring diagram.

Just bought multi meter today I'll check it out. Thanks for the tips I'll post my findings.