There are several heated vests in the market. All have different functionalities and working methods. However, the basic principle of a battery-heated vest is the same.
Here is how to turn on the heated vest:
Use the battery cable to connect it with the battery before inserting it. Before closing the zipper, make sure that you've tightened it. If you want the vest to heat up faster, press and hold the button on the chest of your vest for 3 seconds until you see the red light blinking slowly. This process takes about 5 minutes. It can be done once more to go directly into one of the three modes, which will reduce the "heat boost effect." Different light colors indicate three different modes of heat. Single press the button to switch heating levels between High, Medium, and Low. To turn the vest off, hold down the button for 3 seconds and disconnect it.