If I smoked a fully cooked ham, this is how I would do it.
Precooked hams are usually precooked to a temperature of 152°F, partially cooked hams are cooked to a temperature of 127°F. So check with type you have. It will clearly state it on the package.
If it is fully cooked, you will still need to air dry it. Uncooked cured hams, I generally air dry for 8 hours at a temperature of 110°F - 120°F. This is important to dry the surface of the meat and form a good pellicle so that the smoke will penetrate and adhere better. For a fully cooked ham or precooked ham, I would pat the surface dry with paper towels and air dry in the smoker for 2-4 hours.
Place ham in the middle position of the smoker, rotating the ham from front to back after air drying. Next increase the temperature to 130°F - 140°F; add warm water to bowl, and apply 4 hours of smoke; I used maple.
Since it is already fully or partially cooked you have a couple of options. After the smoke has been applied, you can take it out of the smoker. I like to let the smoke flavor mellow a bit before fully cooking it or applying a glaze, by wrapping in plastic and "aging" in the refrigerating for a day or two. You can skip the "aging" stage. Then finish in the oven like you would any precooked ham. Or increase the temperature of the smoker to 210°F-220°F.
If the ham was fully cooked, you only need to bring the internal temperature to 140° - 152°F or as high as 165°F; what ever you feel comfortable with; but 152°F is high enough. If you started with a partially cooked ham, you will need to bring the internal temperature to at least 152°F.