Hello my fellow VQ Drivers, about a 2 weeks ago l get off work start up my G and there is a brake+Battery light I went home next day got a new battery and alternator under warranty at Autozone.

Issue went away for about 2 days then came back.

Noticed corrosion on the positive battery terminal and positive terminal fuse (left the cover off an some moisture crept in), I replaced both issue went away for a week I also did my drive belt and checked tension. Issue came back yesterday cleaned the battery posts my grounds, checked voltage did voltage drop test. Was reading 14.3-14.7 any help or insight would be appreciated tired of throwing parts at it got a used oem alternator dirt cheap. gonna try that also changed the alternator wire that goes to the fusible link. The alternator nut that goes on the stud is snug. I truly don't know what the issue could be it now only comes on while driving usually under hard acceleration, and most times it will go away while still driving seems like it's not a consistent issue as it has also happened while I was just crusing. then went away a few minutes after. anyway if you read this I appreciate you and let me know if you ever had anything similar happen to your g37 and how you fixed it (2011 370z engine swapped (130k miles) last may (40k miles) 5 speed transmission as well)

 

Check your grounds.
ALL THE GROUNDS.

Check your brake fluid.
Check the brake master and brake light wiring too. From the switch to the BCM, to the ECM, and all the way to the taillights.

You said "swap"
Is your main ground still going through the Amp sensor?
Are you accidentally bypassing the Amp sensor ring? Happens frequently with "grounding kits".
Still wired for "smart" charging? If so i recommend eliminating it.
Especially if you take frequent shorter trips.

 

Aftermarket alternators are iffy. I've seen new ones d.o.a. Mine lasted 2 months before it went bad. Gotta go oem if you want reliability.