I have a 84 300dt when I removed the face plate over the heater ac controls (to replace the bulb in the temp wheel) I found one extra bulb socket not in use total of five. one for temp wheel, two and three for vent control, #4 for fan control and one extra in the back not in use all have small 1.2 volt bulb.ps, light in shifter on and working. Any idea what extra socket is for? Question two all four switches across the top of center dash do not light up. (rear light switch, antenna ,sunroof, rear defrost) rear def lights up when activated. when I pulled out heat controll unit behind attached to the wall was a plastic ring with about six black wires coming out. these wires go up to the four switches on the top the wires end at the switches in what look like what could be a tiny bulb or led. Previous owner or some mech tried to splice one of these little wires together but they have no metal in them they appear to be glass fibers or some other material. do you sell replacments or can you offer any tips on repair. thank you