Q: Heater and oil light issues.

Hello. From what you describe it would appear that your vehicle is experiencing two separate issues. Problems with the heater can be caused by a few different things. The first thing I would check is to make sure that the cooling system is properly filled and topped off. Low coolant, or a system that needs to be bled of air pockets can be cause all sorts of issues including erratic behavior from the heater, and in some cases even engine overheating. If the coolant is at the proper level then it may be possible that there is an issue with the heater control valve or blend door actuator, the components that control the flow of coolant and air through the system. These are located in the engine and interior of the vehicle and are integral to the proper operation of the heater. In regards to your oil pressure light, if you have recently gotten the oil changed then it may be possible that there is another issue with the vehicle that is setting off the light. A blinking light can be caused by a faulty oil pressure sensor or the associated wiring and connector. A test and inspection of the sensor and harness could determine if this is the issue. Similar symptoms can also be caused by a worn oil pump or engine bearings, though this is less likely. I would recommend having a professional technician, such as one from YourMechanic, come to your location to determine what the causing your issues.