My check engine light won't come on.

What is your question?

Failed smog test because the check engine light won't turn on at all. when the key is in the ignition before turning it on all the other lights on the panel light up than go off like they should when the truck is on except that for that one. Could it be a burnt light bulb or a fuse.

How long has your 2002 Ford F-150 had this problem?

For about 3 weeks.