Re: 1998 Dodge van cruise control
first, check any vacuum lines to the unit. some lines are plastic and may look like wires. check all connectors for corrosion ( pencil eraser and wd 40 to clean). fuses are probly ok since it starts. there is usually a vacuum chamber. newest models may go through computer, if equipped, but, don't think that is a problem.
on older dodge vans ( 1979 1986) i have found the vacuum lines or sometimes binding linkage/ cable to be problem. borrow a chiltons manual or look it up on the web, the parts are all accessable and easy to check.
don't give up too easy, it is usually something simple.