The dash cluster switches marked M and R were addressed on 7-15-2003 as part of a dealer ICP notice. Their failure rate was rare and sporadic so NO recall ever issued.
Dealer notice B054: Intermittent or total failure of dash M/R buttons replace entire cluster under specific warranty parameter.
And NO...it has absolutely nothing to do with wiring harness....positive main red wire feed.....fuses....grounds...battery condition...voltage present.
Replace your dash cluster.