No Wait To Start Light ?

2000 F350 CC 4X4 with a 7.3L PSD, completely stock.

When I attempt to start the truck the wait to start light on the dash does not illuminate and the truck turns over fine but will not start. All of the other lights on the dash seem to work fine.

I drove the truck, it was running fine, and then I turned it off. I went to start it a couple hours later and this problem occured. Never had any sign of trouble prior to this hapening.

Has anyone had this same problem? What caused it and how do I fix it. Any help would be appreciated.

Thanks.