1999 Chevrolet Silverado Bought This Truck Uncle S Estate Prndsl Lights Would

When I bought this truck from my Uncle's estate, the PRNDSL lights would not light, nor would the odometer. When I started checking the system, I found evidence of prior attempts to fix this(tie wraps cut on wiring harnesses, extra plug in fuses left in ckt box, unwrapped wiring harnesses). I unplugged the instrument panel, sprayed contact cleaner on the plug and receptacle, and packed dielectric grease into the receptacle. The PRNDSL lights and odometer lights started working, and worked for about 2 years. Now it has quit again. A similar treatment provided no "visible" results. I would like to find a wiring diagram that tells me what pin the power to these lights comes in on, and what path the ground takes leaving the instrument cluster. Every thing else works fine in the cluster.