I don't have the pinout handy, but the CEL trigger runs through the C203. unplug the C203, ground the pin for the bulb (should be a brown wire IIRC.) and that will tell you if it's in the chassis harness or something with the PCM/connectors.
I ran into a similar problem on my 3500 swap, the bulb wasn't coming on. turned out to be a mis-wired PCM.
------------------ we're in desperate need of a little more religion to nurse your god-like point of view...
Thanks guys, I needed to know just that. The actual printed circuit on the back of the dash appears fine, I have had it out of the car a few times. IIRC the light stopped working some time after I set the timing (either immediately or within a few minutes) I did not pay attention to it at the time. It is probably a fluke though I will check the harness itself at the C203 connector and hopefully the test light will light. If not is there a possibility it is internal to the ECM? I can obviously trace it back and backprobe the ECM connector if it does not light at the C203, but if it does not light there... If it DOES light at the c203, then I will check the actual plug that plugs into the dash itself because the printed circuit probably got messed up there if it got messed up anywhere.