The gauges can be bench tested before spending your hard earned money.
The Oil Pressure can be hooked up to an air compressor that has it's air regulated down to about 15 pounds...see if the compressor gauge matched the dash gauge.
The Temp Sender can be put in a pot of water on the stove and tested. Use the wifes cooking therometer to compare readings.
The Fuel Gauge works by varying the Ground/Negitive side of the circuit. Hook 6V + to the IGN or + terminal on the gauge, Ground the gauge housing to battery - and connect a wire from the gauge Sending Unit Terminal to Battery -. If you make and break the gauge sending unit wire you should see the gauge reading do from Full and Empty.
The Ammeter should really be checked in a running car or truck. To bench test you can hook a 6V + to the Bat terminal and a load of some sort like a good heater fan motor from the other terminal on the Ammeter to the + wire on the heater and then connect the heater Ground - to the battery. The gauge should read discharge with the fan running...clear as mud right!
Hope this helps.
Mike B
