Disable Seat Belt Alarm 2013 - Factory method DIY

My 2017 has several “buzzers”, which are electronic beeps. I couldn’t be sure they weren’t controlled in some inscrutable way from the ECU, and I wanted to preserve that brand new truck feeling as long as possible. Note that once I flip a few bits just like the manual says the dealer would maybe do, nobody can tell he didn’t do it - “equivalent to new” as they say. Also eager to get some hands-on experience with a newer OBD interface. I may want to modify the TPS curve to reduce that teeny zero mph hesitation that I wouldn’t have noticed except for being spoiled by my 06 Highlander. And then there’s that annoying disconnect between tailgate lock and door locks (probably not OBD-friendly, and wiring/soldering required)...

 

On the 2nd gens the ECU doesn't care about the dash cluster. When I'm resetting needle positions after changing/removing lights & buzzer I can turn the vehicle on/off with the dash disconnected and no new codes populate.

I'd be interested to know what all secondary systems you lose with a standalone EMS though. If the ECU was disconnected completely and the ignition circuit was powered, would everything on the body ECU function properly? I mostly just care about window regulators, wipers, turn signals, ADD/TC actuators, and brake lights. I'm considering moving to a standalone and I don't have any need for the VSC, ABS, Airbags, EVAP, Immobilizer, etc.