I have79 300SD. I am a little confused with the gauge cluster set up. Parts of the panel work but others dont. The lights that are supposed to come on with the headlight and illuminate the panel dont come on at all. All of the warning or "dummy" lights work at the bottom however the clock and tach do not. The tach jumps around a little at idle but when I get on the throttle it falls again. I understand this may be a result of the sensor on the crank itself and not a gauge problem. I also dont understand how power gets to the driver side dummy lights, the passenger side has wires to the bulbs but the latter only havea black inserts with a bulb in it however they work. Is there a circuit built into the back of the panel? As for the other gauges (oil, temp, fuel) they all work. Any information thatanyone could provide would help me out. I really need to get those lights working so I can see at night!HAHAHA!Any tips with the clock would help as well! Thanks in advance!