MAD electrical upgrade question??

Thanks Ben. The only recent electrical changes I have made.

1. Replaced 4 yr old battery under warranty.
2. HL relay kit in spring. No issues with install. Works great.
3. New alt last year or year before. Great no issues.
4. Some under hood wires replaced/repaired this week (coil neg to bulkhead gray, blower mtr green wire to bulkhead, fusible link connector cleaned, added external ground from VR mount to batt -ve) This was done this week.
No signs of issues until 3weeks ago when alt gauge started to fluctuate also one instance there was an odd smell that did NOT originate from me.

Thanks!