what makes a warm up light work on 1995 Ford F-250

the light will not come on and it will not start does anyone have any suggestions on how to fix this problem

Asked by for the 1995 Ford F-250
Sounds like you have a glow plug problem - either a glow plug wiring harness issue or a controller issue. Could be glow plugs themselves, but if the light is not proving out, then I suspect something more controlling than the end glow plug.