1990 Plymouth Acclaim blower and rear defogger suddenly sto

Heater problem
1990 Plymouth Acclaim 4 cyl Front Wheel Drive Automatic

I checked the fuses and all are good but the rear defogger doesn't work and the heater blower doesn't turn on. They both stopped working at the same time so I assume it is either a connection or a relay. I do have a repair manual and just need to know where I should start first.