The heater in my car just stopped working the other day. No air comes out at all. A few days later it started working again, only to stop last night. Sometimes I feel a tiny bit of heat at the vents, but other than that no air will come out at all.
Is there any reason this would start and stop like this? Or anything I can check on my own before visiting my mechanic?
Your statement that "no air comes out at all" to me indicates that the blower/fan is not working. This could be a problem with the blower switch/speed control, the blower motor, the associated wiring, or a fuse which protects all of the previous.
I would remove the blower (often accessible from the engine compartment, on or near the firewall) and test it to see if it is operating. if not, you would need to troubleshoot to find the fault. If it is working then you would investigate for a possible blockage, perhaps an issue with the temperature blending gate/door.
The fact that you "sometimes... feel a tiny bit of heat at the vents" could just be air blowing through the ducting and across the heat exchanger, due to driving speed.
This could be something as simple as a leaf stuck somewhere in the vents.
I've had this trouble before, a simple leaf sucked into the heater air intake blocked the airflow. However, the heater fan motor could be heard louder than usual as it struggled against the resistance. Also, with the fan full-on, the leaf could be heard flapping.
You could try poking something flexible carefully into the heater vent.
