How to check dashboard lights in a 97 GMC Safari Van

Check your switch that runs to your aternator.make sure is grounded .if not get a sand paper and sand it down.also check the switch that plugs in to the alternator.

take starter off and check directly with battery, but sounds like battery from symptoms

You & we need to know what it failed for

What Emission Gas & what are your State limits
& what did your vehicle read?

You can study exhaust gases on the internet & see
what area of the vehicle needs work based on the gas
readings

Have to educate yourself

Do not wait for someone to tell you things

You won't learn or remember if you don't
study on your own or don't start a binder &
take notes & copy web site info,punch the holes
& put in the binder

Then you take your info out to the car & make the
tests & fix things

look in the engine compartment, look for the +battery cable, usually red, follow it to a black plastic box. it should be very close to the battery, take the top of the plastic case off, there should be lots of fuses and relays inside.

Sometimes the emission light will come on if the gasket on the gas cap is worn or dirty, thus not sealing properly. If it doesn't look worn, then try cleaning it.

What fault code is being set?

They don't usually go bad, but your problem does point to that as a possibility. If your check engine light wont work is another sign.

Is the headlight switch turned all the way to illuminate the dashboard lights? If it is, check the fuse for instrument panel, also marked as instrument cluster.

There are a few thing I need to know, what engine do you have, how many miles on the van, what part(s) of the test did it fail?