In Sharon’s election on Tuesday, Selectman William Heitin faces a challenge from Steven Ross, a primary care physician who said he is running, in part, because his patients tell him they are moving out of Sharon because taxes are too high. Ross also said he would like to make government committees more representative of Sharon’s diversity. Heitin, a partner in an asset management firm, said he hopes to complete ongoing initiatives, such as attracting businesses like the Sharon Commons development that will shift some of the tax burden away from residents. He also aims to identify a new public water source, he said, and to see to fruition a solar facility that would reduce town electricity costs by about 50 percent. In another race, for School Committee, Marcy Kaplan and incumbents Jeff Cruzan and Emily Smith-Lee are running for two seats.