Step-By-Step Instructions

1. Locate your main control unit. It will likely be in a basement, closet, or crawl space, and may be grey, beige, or black in color. For AES radio, the unit will be on a higher level in the home and will have an antenna coming out of the top. 
    
2. Open the door to the main control/AES. If you do not have a key, check the top of the control unit. 
    
3. Disconnect the black and red connectors from the top of the old battery. 
    
4. Install the new battery in its place and reconnect the black wire to the black lead and the red wire to the red lead.