Note: I did this on a 95 Escort GT, should be similar though::
Take out all the screws on the bottom of the black dash panel, and remove the plastic steering wheel column cover (two plastic bits that snap together. Pull out the black dash piece, uses a lot of force because you have to squeeze it past the steering wheel and the rest of the dash (it can be done, takes a lot of force though (make sure you unplug the rear defrost unit if you have one) note: I read in a manual that you can take out the steering wheel and it makes it much easier - I didn't know this and took it out with the steering wheel still installed)).
Then there is a bunch of little screws to undo (make sure it is not the ones that hold the plastic cover down). Follow the speedo wire down to where it connects to the transmission - you pull out a little metal clip that holds it in and then pull it out (this gives you room to pull the speedo out. When you can pull the instrument panel out a bit, undo the little wires in the back that plug into each of the smaller gauges and then there is one humungous wire in the back for the speedo. Pull that one REALLY hard until it pops out - don't worry it won't break. Then repeat until everything is back.
The hardest part was probably getting the black dash part out past the steering wheel - this would be much easier if you know how to remove the steering wheel.
When you take the two pieces off of the steering column there are four bolts under the steering shaft that attach a plate. Take the four bolts out and the steerin wheel will drop down to allow you to take out the dash liner.
Inside the instrument cluster. To replace them remove the cluster and take it apart.
Behind the instrument Cluster. Or remove it and replace the Cluster.
The instrument cluster needs to be removed to get at the bulbs.
Remove the dash and remove the instrument cluster, the lights are in the back of the cluster.
remove dash replace bulb(instrument cluster)
The entire instrument cluster must be remove to replace lamps. If equiped with Electronic cluster, it might be better to take it to the dealer.
well i bought new lights for my instrument cluster thinking it would fix the problem but there still dim
you cannot service panel lights on 2000 impala . you hav to replace the instrument cluster.
Replace the light bulbs that are burned out, usually from the back side of the instrument cluster.
Dashboard area where guages, speedometer, & lights are located
Below the instrument cluster is a trim piece that goes across the width of the instrument cluster. Remove the 4 screws then remove the trim piece. Remove the screws that retain the instrument cluster, then carefully pull the instrument cluster STRAIGHT BACK. The instrument cluster plugs in to a matching socket in the dashboard. Be certain that the pins do not get bent. It's a good idea to replace all of the bulbs once one burns out. The rest will be failing soon. There are two types of bulbs used in the dashboard, they might only be available at a GM dealership. Replace all of the bulbs. Carefully push the instrument cluster back into the dashboard, then test the lights and make certain that the instruments and indicator lights work before putting everything else back together. Replace the trim ring around the instrument cluster. Replace the bottom trim piece... Done. ... at least, that's how it works on the 2000 LS
You Will Have To Take To A Dealer. Best Of Luck