1992 Saturn SW2 ALL gauges including speedeometer and odome

Computer problem
1992 Saturn SW2

When I purchased the car last year, the odometer did not work, nor did the temp gauge. Recently, the fuel gauge went to zero and won' move. Alsoi thespeedometer reads 80 mph when the key is on Coolant level & Anti Skid lights flash. I have been told that one senbsor controls all of these. Is this correct and if so where is it located? Thanks, Jerry