Do a continuity test back to the glow plug controller.
I think somebody, maybe @Glagulator posted the type of wire and connector needed not terribly long ago.
I'm old, so that means in the last 4 years.
There are good glow plug wire kits to be bought
Depends on your budget and if you...
Only buy the ACDELCO 60G glove plugs from a known vendor.
I have a friend that cussed 60G glow plugs - I really believe he got some counterfeit.
I used to buy them at Autozone.
I don't know who sells ACDELCO 60G glow plugs now
I'd still just as soon hire someone trustworthy to get it done, so I can use it
It'll be a long while before I am able. Yesterday, I walked 1/4 mile, clipped a few weeds and I overdid at that.
I tried that on the 1998 and ended up just getting a new board.
Might try searching wiper board
https://www.thetruckstop.us/forum/search/1160717/?q=Wiper+board&o=date