heater blows cold air just replaced module

Hello,

There are few reasons why a heater can blow cold.
It could be for low coolant level, clogged heater core, a stuck open thermostat, blend door actuator stuck on the cold side.
First make sure that the coolant is at correct level.
If you have a stuck open thermostat, then the engine will not reach the operating temperature. Make sure that the temperature is at the correct level during normal engine operation.

The blend door actuator is located inside the dash on the HVAC box. It controls the hot and cold air. Many times the actuator can fail at either the hot or cold side. This will prevent the heater from working.

Here is a helpful article that covers the typical issues for a non working heater:

https://www.2carpros.com/articles/car-heater-not-working

Please let me know of any questions.
Thank you.