When I have the key in the ACC position it should provide power to the radio and other components, and mine always did. It recently stopped doing it though. The ignition switch is relatively new. I noticed one time that the ACC power went off if I lowered the tilt all the way down and put a little bit of pressure on it, but now it does not work at all.

Two questions - 1) is there a common failure point for these before I dig into the column?

And - 2) I can turn the key forward to the ON position and play the radio. There is no issue with chimes or buzzers. A couple of the idiot lights come on the dash, which is normal. I know that in older cars with points you weren't supposed to leave the key in the ON position because it would burn up the points - but are there any issues about leaving the key in the ON position with my 1990? The owner's manual does not say anything about not doing it.

Thanks

 

No, there our no issues with leaving it one, cause on a truck with points if you left the key and the points were closed, then you could burn them or the coil. You 90 is electronic ignition, and it has a magnet therefore there is nothing that can be burned up.
As for your acc power problem, I would check the ignition switch mounted on top of the column under the dash, they are a common problem after so many years the plastic part can seperate from the metal plate and cause all sorts of hell, also see if maybe the screws just did'nt come loose and its out of alighnment.
hope this helps.