Gas gauge

[Johnnydidd]

Just hooking gas gauge on my 56 Merc. the gauge with an ohm meter set at max or any where in between will show continuity. the wire running to the sending unit shows nothing, any ideas? this is the first its been hooked up. I think it must be the sending unit.

 

[dmsfrr]

Check the continuity of the sender with your Ohm meter as directly on the sender as you can.
Is there an access cover in the trunk floor? Also double check that the tank itself is grounded to the rest of the car, and the sender body is grounded to the tank.

There should be a resistance reading thru the sender.

 

[Daves55Sedan]

To conduct a test of the gas guage using an ohm meter, first you MUST DISCONNECT the power wire from the gas guage.
Make sure your batteries in the ohm meter are good.
Touch the ohmmeter probes to the two terminals at the back of the guage. (BE CAREFUL TO AVOID TOUCHING ANY OTHER GROUNDED METAL PART UNDER THE DASH WHILE TOUCHING THE TERMINALS).
With gas tank empty, the reading at the ohmmeter should show a higher resistance (around 60-70 ohms not sure exactly).
With gas tank full, the reading at the ohmmeter should show a lower resistance (around 10-15 ohms not sure exactly).
If the reading at the meter is zero, there is something wrong somewhere.