Bricks, Masonry, Asphalt and Concrete - cracks in brick wall

My house was built in 1965 of concrete and brick. On the non window brick wall about 10 feet from the front there is a step crack that runs from just under the eaves to the concrete wall which is about 4ft high. There are no cracks in the concrete. This has been there a while The width of this step crack varies from about 1/16th to 1/8th of an inch and passes through the middle of some bricks as well as the mortar joints. This morning I checked the depth of this crack and the thin bladed knife I used went in over 5 inches!
This wall is one of the master bedroom walls and frequently both at night and during the day a cracking sound seems to come from the area where the outside step crack is. Should I be overly concerned with this and if not how do I go about fixing it?
Thank you for your help.
James Sheen.
P.S.I live in Roxboro Quebec where temperature change is quite common year round.

Is the crack from the top corner of an outside edge moving down? Generally, when the crack passes though brick, it is indicative of a structural failure (but not always).

Hi Tscarborough,
Thank you for your reply. No, the crack seems to begin about 10 ft in from the wall's outside edge from under the eaves. Not all bricks have the cracks. I believe this situation existed when we bought the house in 2000. I seem to remember the building inspector at the time felt it was common but nothing to worry about! Any further help would be appreciated.
Regards,
James Sheen.