If your vehicle is showing dashboard plastic is sticky or melting, here are the most likely causes and the parts you'll need to fix each one.
Prolonged exposure to heat and UV rays causes the chemical plasticizers in the dashboard material to break down and seep to the surface. This is a widespread manufacturing defect in many mid-2000s to early-2010s vehicles.
Using harsh solvents, alcohol-based cleaners, or incorrect detailing chemicals can dissolve the protective clear coat or top layer of the dashboard vinyl, leaving a permanently sticky or melted surface.
Double-sided tape or adhesive pads used for aftermarket phone mounts, GPS units, or dash mats can melt in high cabin temperatures, leaving a gooey, sticky spot that chemically etches into the plastic.
A leaking heater core can vaporize engine coolant into the cabin vents, leaving a sticky, sweet-smelling glycol film across the dashboard and interior glass that mimics melting plastic.