After 4 years it is just occured to me that my check engine light has never once tried to help me. After all the problems I faced to keep my 21 yr old alive, that light has never come on. Im pretty sure that I've been in some situations where it damn well should have clued me in on something.

It only lights up when the truck is first started. How can I tell if it is hooked up properly?

 

The CEL usually only comes on if something is easily detected and horribly wrong. My guess: it's working fine and you just haven't sabatoged you engine enough yet to need it...

EDIT: Besides, if it turns on for a brief while while you start your engine, that means its working fine.

 

Sounds to me like you've just been lucky. Mine hasn't come on in the last 3 years, but 21 years is pretty amazing!

You can also do the paper clip CEL test to see if you get any codes. If you do a search for this, you should be able to find out how to do it pretty quickly.