The Regal and Century's have a problem where the odometer will become dim and nearly impossible to read at anytime of the day/night. Some Regal were equipped with a cluster that had a DIC or driver information center that can suffer same problem. To fix this you will need to remove the dashboard bezel to remove the cluster. Then open the cluster and solder some 1/4 or 1/2 watt 150 ohm resistors on the cluster circuit board.
Open both front doors
Remove the end panels of the dash (on passenger side this is the fuse cover.
On the passenger end, remove one 7mm screw from end of dash trim panel.
Open glove box door
Remove one 7mm screw from the lower dash panel that is to the right of glove box door.
Pull that lower dash panel toward the seat quickly and the clip will release.
Remove the driverside lower dash panel by tilting the wheel all the way up and removing the two or three clips/7mm screws holding it at the base of the dash.
Pull that forward/upward like the small piece on the other side. Unplug the wiring to the button pod on the piece.
Start at the passenger side pulling the dash panel forward to unclip it. You will notice it is behind the piece of the center console. Work past this to the driverside. When all the clips appear loose, wiggle and jockey it to get past the center console.
Remove cluster by pulling out four 7mm screws that hold it in and then unclipping the connector that goes to it.
Needed:
Soldering iron
10 or less 180 ohm resistors. (1/4 watt or 1/2 watt, either will work well)
To open the cluster gently pry the black back off the cluster by lifting gently on the black piece at the arrows. Usually lifting two or four is all it takes for it to come off.
Here are the two pieces.
Grasp the circuit board and wiggle, it will seperate from the rest of the cluster.
Put your black back piece and main cluster piece off to the side and out of harms way. Place the circuit board on a towel or other item that will not hurt it. Looking at the circuit board there should be barrel resistors in the circled areas. If you touch them, likely they will crumble and fall off. Remove them if they are there. (Century and non-DIC Regals will have fewer than this picture, only replace ones in the circled areas)
(Note: prefix pic not available.
Now solder your new 180 ohm resistors onto the board where the old ones were. I only have experience with 97/98 clusters, they have traces and holes through the board for most of the resistors where you can hold an iron to a solder dot on the back of the board and push the resistor through. If you have this style circuit board, it is easier. Here is Rick (DeMonte) demonstrating. It is his first time and it came out great.
Here are the remainder of the resistors in place
4 here
4 here
And 2 here
Reassemble your cluster by pushing/wiggling the circuit board back on the main cluster and then pushing the black back piece back onto the cluster.
Plug it in and try it before you reassemble the dash.