Plenty of air but no heat one side of dash use to blow hot air. Now neither side blows hot air. 2000 jeep grand cherokee coolant is fine driver side seat heater doesn"t work air bag light comes on every once in awhile. could it be electrical? or heater core? It's freezing in MO

Check to see that the blend door linkage is hooked up. Doubtful it is heater core, as you had heat to one side and not the other. Check coolant control valve linkage, verify it is moving the coolant valve from off to on when you switch temperature from cold to hot. Verify you have coolant flow to the heater core by feeling the heater hoses where they enter the firewall. If all checks out well, then look at hvac controls individually.