99 Dodge Dakota, blower works fine, air temp out of any of the ducts is luke warm at best. Engine temp (according to guage) never goes above 170 even in the summer and radiator cover with card board!

First, replace your coolant temp sensor to be sure youre getting a good signal to your gauge. Then test your mechanical fan to make sure its working properly. A bad fan clutch will keep the fan on at all times and keep coolant temps way down, and rob fuel mileage. Test or replace your thermostat to make sure its on working order, it may be stuck open. When youre sure the cooing system is up to par, and the heat still doesn't work, try flushing the heater core and/or the entire cooling system. Dakotas and durangos are known for clogging heater cores.