In order to isolate the problem, we will need to do the following test procedure. Hope this is helpful.
Test for 12 volts at the BODY, LOCKS, LIGHTER, and CHIME fuses in the Instrument Panel Junction Block (IPJB). If ALL of these fuses do not have 12 volts on either side, disconnect the Black 68 way connector on the left side of the IPJB. Inspect terminal F5 for overheating. This is a 3 millimeter wire. If the terminal is overheated, replace the terminal. Inspect for melted connector body and heat damage to the IPJB. Replace as necessary.