Gas Level Gauge (Datsun 620 '75)

[Droski]

My gas level gauge went from working to not working today , needle is at past empty (happened after visiting a gas station/has fuel). Fuel sending unit ? 

Edited December 13, 2019 by Droski

[Draker]

Contacts might be dirty on the sweeper in the tank. If you pull the wire off and ground it, the gauge should read full. If it does then the issue is the sender. Probably just need to clean it. 
 

 

[Droski]

I appreciate your help 🙏

[datzenmike]

Not sure if there is only the one wire to the sender in the tank. If so the tank is grounded. Loss of ground will also cause the gauge to not work. Make sure the tank is grounded.

 

The wire from the gauge may also have corroded and fallen off. It's bundled into the rear light harness and clipped to the frame so is very exposed to rocks thrown by the tires.

[Droski]

also forgot to mention that my temperature gauge is also not working, didnt notice it at first but both are not reading 

could this be an electrical issue ? 

[bilzbobaggins]

Most likely a voltage regulator problem that is located inside the 620 cluster.

 

 

Edited December 20, 2019 by bilzbobaggins
added stuff

[datzenmike]

This!

 

Remove the temperature gauge and locate the contact points. Fold a thin strip of fine emery cloth and place between the contacts. Pull the emery cloth out several times to clean them.