Nissan Repair: heat, sentra, probable cause

Question
2005 sentra /heat works good 5 days out of seven.idid the lift the car up off the ground and it works for a while .then it stops.

Answer
Moe,

I need to know if the blower is working and the heat stops or the blower keeps working but blows cold air.  If cold air then you need to look at a thermostat replacement as the most probable cause.  If the blower stops working then you are looking at the control, the resistor or the blower.