1998 Toyota Avalon wipers, windshield & visibility problems

Electronic climate control and dash lights/warnings cut off without notice and cannot be restarted unless ignition turned off and allowed to sit >1min, dealer cannot identify specific problem recommends trying to replace module for $1200 although that may or may not fix problem, more frequent failure in summer months

On a 98 toyota avalon xls: the A/C and heating system shuts down completely occasionally. The front and rear defoggers fail also. When the shut down occurs, the air vents emit very hot air, even though the thermostat is set for A/C. I almost had an accident when it started raining and the defoggers failed to operate. It appears to be an electrical wiring defect for which I have appealed to toyota to take responsibility,but without any success