Thankfully, a crack in brick veneer is not hard to fix at all. They happen for many reasons mostly because of settling. Here are a few steps to help if this happens to you.
Step 1 - Remove Any Excess Brick
When there are cracks in the brick veneer you will want to use a grinder with a small diamond blade as well as a chisel and hammer or a drill to remove any of the brick that is coming out or loose. Once you got that out you will want to remove the front of the brick veneer. You can do this as well with the same tools. You will want to carefully and slowly chisel out the top layer as far as any of the cracks went or to about an inch and a half.
Step 2 - Drill Holes
Now that you have removed the top layer you can use the drill bit to make several holes on the front layer of the brick. This is so that the mortar will sink in and attach it to the brick and become secure. Once you get the holes made you will want to try to clean them out as best as you can. Make sure to wear goggles during this step.
Step 3 - Find the Right Mortar
There are a few ways to go about finding the type of mortar that will match the other bricks around you. You can have a professional come out and match it for you or you can bring in the top of the brick that you took off and try to have someone help you in the store. Either way, you will need something to match it to. If the brick is older, you may have trouble finding the same mortar, however, many different combinations of brick and mortar are available to create the right match. If you do not want to be bothered with the mixing yourself, look for companies that have been around a long time to see if they can match the brick. This, however, can take a lot of time and even money. When you do find the matching color you may want to either buy extra of it or at least take note of the combinations so that if you have the same problem in the future you can get through it without this step.
Step 4 - Mix and Fill
Now that you have the correct mortar you can mix as per the instructions and then lay it on top of the brick that you just prepared. Once it is laid you can even it out on top and let sit. After about 20 minutes you will want to score the top a little to make it look like the rest. It will be a little darker for the first week or two but then it will fade to a good match.