I have a 2003 dodge 2500 5.9 Cummins diesel that the cruise control light comes on but when you try to set cruise control it will not set . I have looked for a fuse but can not find one for cruise control. Any help would be appreciated.

 

There is no fuse. On the older trucks, the cruise servo was under the battery.... which led to the obvious problems. First thing to check for though, is to make sure the vacuum source for the cruise servo is actually doing its job.

 

The vacuum pump is located behind the passenger battery on the fender. Very common for the line to develop a leak and the pump runs excessively sucking in dirt ect and burns out. You should hear it "prime" up when you turn the key on, it should pull to a certain vacuum "pressure" and shut off, if it runs continuously you have leak and that's your problem. If it doesn't run at all that's the start of your problem. Follow the line across the cowl and to the servo under drivers battery. I believe there was a connection into the cowl also for a vacuum reservoir.