so... I'll start here I have owed this car for 12yrs. I installed an after Market head unit Clarion NX501 with the metra access gms-01 and PAC swc (10+years ago). after a year or so the metra interface died. I replaced it with the PAC RP5 GM-11 (one module instead of two). worked great.
Fast forward 2019 cart gets broke into head unit gone. but they were nice enough to not cut the wires. I installed the factory unit since I was frequently in a less than desirable part of town.
Fast forward 2020 I had purchased another head unit and interface for a GXP that I bought and sold without installing. so decided to install the unit into the 04 GTP Clarion NX605 harness is the same so why put the new interface in. Used the old one worked great. f
Fast forward 2021 car will not crank not even a click, VIC/DIC blank RAP & keyless entry inop. scoured every thread of this site and google and found many wiring issues that could cause this issue. ripped car apart. ran power probe everywhere checking for shorts/grounds. phone rings I answer and cant hear anything... I'm getting there, but to understand I have to be thorough. Story goes the radio turned on and was connecting to Bluetooth. I had manually turned it off. So okay interface jacked something up. pulled radio fuse. display worked car starts right up re install radio fuse, radio inop. okay back to interface talked to a stereo guru and he said to check for firmware updates. Yep were lots of different updates. performed updates radio works car starts fine all gauges reading like they are supposed to. No keyless entry. Locks work fine with switch, and when trying to re-learn key fobs I get b3101. any Ideas?
and yes I disconnected the battery during every step that required changing or removing any electrical components