Welcome to Just Answer,
The wire leaving the Panel Dimmer to control Instrumentation Illumination is LB/RD which is a Light Brown wire with a Red Tracer (Stripe).
This wire can be found leading to all of the components that require dimming, Instrument cluster, Radio, control switches on the dash and doors.
Hope this is the information you were looking for If not please reply back
You could tie into to the park lamp circuit but this would also add amperage to that circuit, you should be ok with the LB/RD wire, the factory does add a little extra amperage rating in the fuse selection.
I just had to add a little "disclaimer" there, any time you add aftermarket accessories.
I've seen this done many times with no problems.
Arrg, My fault,
sorry LB is light blue,