If I remember correctly the fuel sending unit has a resistance from 10 to 80 ohms. 10 ohms means your tank is full. So if u pull off the cconnector at the fuel sending unit and get a short piece of wire and ground the correct terminal of the connector to the chassis, you will have full deflection of the meter. If u have the meter out, just ground the low side to the chassis instead of getting under the car. The oil gauge is easy too. Just remove the wire at the sending unit and touch it to chassis ground (make sure you have a good connection to ground) and you will see full deflection of the meter. It will be all the way to the right. Note: for both of these the key has to be in the accessory position I believe. Temperature gauge, same as the oil gauge. Remove wire at the sender (which is in the intake manifold) and touch it to ground and it should defect all the way to the right. The ammeter is a shunt meter which basically has a fraction of the charging current flowing through it when ur car is running make sure all lights and accessories are off. The pointer will usually be toward the charge side (right of center). Then put ur lights on. See it move slightly to the left of where it was. Then step on your brakes and see it move more to the left but still not to left of center. That is how that gauge works. If it is reading toward the left of center (discharge side) then something is wrong - either the charging system is not working or the gauge is bad or the battery is bad. If it is reading discharge, your battery is supplying more current than it is taking in by the alternator. This is not good. Like ur alternator belt breaking. Hope this helps. Also I thing all the gauge are powered by a regulator which converts the 12+ volts to 5 or 6.
