Same story with mine. Evaporator had a leak and was replaced, but even though compressor sounded awful they wouldn't replace it as it passed all the service checks. Had a 15 GT do the same and it grenaded sending black sludge throughout the A/C system requiring $2k+ of parts and labor (but Ford...
I decided to try the S&B/JLT closed box CAI. Fit and finish are nice, install is simple, two lid options for additional air flow.
Sealed box definitely helps funnel air from outside engine bay, however too much stop and go does seem to become a heat soak issue with increased IAT for some period...
Duralast Marker Light Socket 853 is the top one
Also there's this option: https://www.diodedynamics.com/wire-harnesses-for-2015-2021-ford-mustang-sidemarkers-eu-au-set.html
Oh there is this one but you'd still need the switch as it sounds like the harness is included (possibly different wiring configuration and plugs as it's marketed for EU) but I've been hesitant to try ordering it with customs charges and all...
Well Shelby still makes it, however it's only available with the brake duct package and you'd need the Starkey harness and OEM switch to keep it factory clean install.
https://www.shelbystore.com/product-p/17bdkit.htm
2016 does it for me also with latest Sync version. Once my lights turn on in lower light I habitually tap the dimmer once to bring it down. I'm curious if it was related to Android Auto or similar, i.e. my phone is always in dark mode - either through selecting dark theme or forced with...