OD-off button doesn't work

1998.5 Ram 2500HD Club Cab, ISB Cummins, 4x4, auto. I think I've found enough info to deal with my cruise control, but problem I haven't been able to find anything on the OD-off button not working -- dash light doesn't come on either. The trans shifts into OD as it should & for the time being I'm not carrying heavy loads or pulling a trailer, but I will be & need that OD off function to work.

What's been done recently: new Blue Chip VP-44, top-of-the-line w/new Frieghtliner computer (engine runs better than it ever has); new battery terminal ends, wire-brushed battery posts, both batteries good; checked all fuses, interior panel & underhood both; throttle cable bracket/housing double-check (cable to trans was a too tight -- stayed in gear too long before shifting) & I've gone over all wiring I can get to without taking things apart, nothing I can find wrong there.

- Art Northrup, Jr.
AA, AS, BSME
art_njr@charter. Net