I never did get a chance to really dig arround and resolve this issue. I'm 99% sure that my issue is electrical in nature. Heck, I've probably only driven the truck 4 times for less than 20 miles since posting this....

The other posts really helped me track it down. I did find that if I drove for a few miles, while shifting in and out of 4, it'd eventually come on. If you can get yours to come on, them it might be electrical like mine. Otherwise it's probably vacuum.

Sorry I can't be of more help, and good luck resolving the issue.

Cheers,

Brian M
'97 T100 SR5 4x4, with Buckets