Diswasher not heating water

check your connections under the sink. A dishwasher (unless it is a commercial one) is not built to heat water the water is supplied via the water heater via the sink angle stop. The dishwasher does however have a heating element inside used to dry the dishes. I would check the hot water side of the sink where the dishwasher is connected to see if the problem could be in that area. Check your setting on the machine. Good Luck on your repairs

Dave