The rheostat (instrument cluster illumination dimmer knob) controls the instrument cluster illumination and the radio illumination. If this dimmer is not working or the ground supplied to this dimmer is open will cause the lights no to work. So, if the relay (titled tail lamp relay") under the driver side dash is good and fuses are good. That leaves a wiring issue, instrument cluster or dimmer switch.
As for the fog lamps.
Check the 15a fuse in the under hood fuse block and relay. If these are good suspect burnt out bulbs, bad ground circuit, or an open circuit.
There is small black diode (a diode is a electrical one way gate, allows current to flow from point A to point B but not from point B to point A) for the fog lamp circuit. It is located under the driver side dash close to the fuse block it is usually taped up on one of the wiring harnesses under there.
I've seen more of these diodes stop working more than any thing else effecting the exterior and interior illumination.
Let me know what you find.
Thursday, November 21st, 2013 AT 5:27 PM