Heater cuts out after a few seconds

Are we talking about the blower motor cuts out or the temperature goes to cold? If it goes cold you want to start by making sure the coolant level is correct. Check this when the engine is cold. If its ok you could have an open thermostat. If the blower fan is not working you can check over fuses and power to the motor but a professional diagnosis is recommend. Here is a link to find a shop near you.https://repairpal.com/repair-shops Alex