So I removed the unit once again. All contacts are clean at the bottom and the metal disk under the float is clean as well. I then connected the unit (without putting it in the tank) and the gauge is working fine, however even when the float is at the bottom making contact with the 2 lower contact points the light does not come on.....

Also, when you turn the ignition on, I understand the light should come regarless of float position. I am trying to find out if it comes on as a test of the sending unit or as a test for the light????

I wonder if anyone would know how to test the gauge for proper operation using a voltmeter.

Thanks

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1980 300TD(euro non turbo): Eng: 617.912 /Tran:722.118
1985 300SD: Eng: 617.951/Tran: 722.416