Modern Vespa

I have a '97 Vespa ET4 and currently, the odometer is stuck, the speedometer is stuck no matter if on or off, the fuel gauge is inaccurate, the fuel light flickers on and off when low on fuel, the oil light does not come on when you turn the key and the standard green lamp light doesn't work (otherwise it's ok....)

What is it I need to have this resolved? New dash panel? New wiring?

I'd open up the headset and have a look around. Fuses might be bad or the little lights might be blown (be careful because the tabs that hold the headset in place are crap,break very easily). Your fuel light is supposed to flash on and off. You usually have about 20 miles of fuel left when it flickers (maybe more). My fuel gauge has always been inaccurate. When i first got it,it stayed on E when full. Now it's full on 3/4. You just have to see how much you put in and how many miles you get when you fill it up. Speedometer may need a little grease to unstick it. The odo cable might have come unscrewed. Might need a new one. The bikes getting old so a little work on the bits might need to be done. Wiki section section has tutorials on most everything. I's swap out the fuel lines if they haven't been done. Bikes 18yrs old. Hope this helps. Plus you live in a harsh environment (rainy). White Lithium grease on things will help your cause. Good luck