My '04 is supposed to have a dash light that tells you when to shift, mine comes on at startup but I never see it again after that.

Not that I need to be told when to shift, but it might be useful for my 15 yr old daughter who's in driver training.

So dash light works, what else might it be?

 

It's programmable by the dealer. Depending on the engine it may/may not be enabled.

You need a DRB to program the instrument cluster.