Dash Lights Out... Add Rheostat for dimming

[frontporch]

I have a 2005 Honda Odyssey that has dash lights that are a combination of LED and incandescent. Most of the incandescent lights do not work. That results in my radio backlight and most of the buttons being off. I have tried to track down this issue and haven't found it. The factory dimmer is built into the cluster and uses a transistor to change the ground and dim the lighting. I have plans to try and swap the cluster with another, but was also considering changing the wiring to include a rheostat. I came to this forum for some guidance to see if that was possible. The van is older and is going to be retrofit for a mini camper. I don't mind drilling holes, splicing wires and adding dials to get this basic function working.

Thanks in advance for the help.