yeah when you first turn on the key it goes through a self test and then if there are any codes after like 45 secs or i think it is less but it should blink any stored status codes.
Now if there are any faults that are active when the key is turned on the MIL light will light up, and also one of the other indicator lights related to the system with the fault, and the MIL light will start blinking the code associated with the fault. If there is no code present and the MIL light stays on then do the following:
-Key off
-disconnect the ECM wire harness connector C001
-using a digital vom meter check for continuity between ECM terminal 26 and battery voltage
If you have continuity repair the shorted ground circuit as necessary.
If you do not have continuity then replace the ecm.

I have read one of your earlier posts about this light, about how to wait 45 seconds after key on engine off, but this machine never blinks any codes. It just stays on until you turn the key off. Any more help would be appreciated.

Set # AF17C00583. The light burns bright when it comes on, and stays on until you turn machine off.

is that the only indicator turning on? No other ones lit up at the same time?
is the ! blinking any? or on steady?
is it bright or dimly lit?
If no other lights are on and it's just the MIL light then it may be an 02 sensor issue, either running too rich or too lean or the 02 sensor heater might be faulting.

what is the truck serial number?