Preheat a grill pan.
Coat the corn with oil and place it on the grill pan. Turn the corn frequently to achieve charring on all sides, which should take about 6 to 10 minutes.
In the meantime, prepare the seasoning by mixing together mayonnaise, chili powder, garlic salt, and black pepper.
Once the corn is done grilling, brush it with the seasoned mayonnaise mixture.
Serve the corn with lime wedges for squeezing over it.