I found the blinker/hazard light relay but that wasn't the problem. MBenz hit the problem on the head... My mom's a smoker and flicking the hazard light switch back and forth 20 times or so caused the blinkers AND the hazard lights to begin to work again! I could have been the residue from the cigarette smoke mucking up the switch or it could have been the cigarette ashes that keep falling down on top of the switch.
Besides, she drinks (and spills) coffee in the car and maybe some of that got onto / into the switch. Next time she's at the house I'll pop the wood panel up that contains the switch and spray the heck out of the switch with some electrical contact cleaner.
Thanks for everyone's help on this.
Scotts Valley, CA.
1993 300 CE Cabriolet (A124) 131K miles
1997 C-280 133K miles
2000 BMW R1100RT 69K miles
1989 300 E 216K miles (sold)