Re: 94 Marada - Help!
The speedometer not working has absolutely nothing to do with the other failures because it works on water pressure compressing air in a tube. No electrics involved at all except for the internal light. If some of the gauges work and others don't then there is a wiring issue between the gauges because they are simply daisy chained from one to the next. If they are all inoperative, then you need to check for power (+12 volts and ground) feeding them. +12 volts comes from the "I" (ignition) terminal on the ignition switch. Ground is werever you find it but usualy at a ground buss at the helm. Gauges like the fuel, temp, oil pressure, tach, etc have a "sense" signal that comes from the engine or the fuel sender in the fuel tank. Each of those signals connects to the "S" terminal on the appplicagble gauge. If that signal is missing the gauge will not work. Missing the sense signal from one gauge does not impact another so the fact you have several non functioning gauges says +12 volt or ground is missing. No power to the radio says fuse. A stalled bilge pump should also have blown a fuse unless it was the float switch that stuck and simply allowed the pump to run continuously. When you leave your boat ALWAYS do the LISTEN TEST. You listen for anything running.
