Fuel Gauge

[Iffy650]

I'm restoring a 1989 air cooled 126 and thought I'd check that the fuel gauge is working before I reinstated the fuel tank so I put the battery in (new) and connected the wires on to the sender/float unit (new) and turned the key . Nothing.
Check the wiring diagram to ensure I'd got the connection onto the sender/float unit correct.
Check fuses were all ok. Checked connections back as far as I could.
Got my multimeter and checked that there was voltage across the wires, got about 3Volts.
Any ideas?

[ChrisRLewis]

Take the electrical wire off the sender unit and ground this wire to earth (with ignition on). If gauge goes to the full tank reading it will indicate that there is a fault with either the sender unit or the tank is not earthed.

[Iffy650]

Thank you Chris,
The gauge didn't go to full when I did that.
Perhaps the gauge or connection to the gauge is faulty?

[ChrisRLewis]

Is the fuel tank installed in the car? and if so is the tank grounded to earth? Also check to see if your brake lights and indicators are working because they are on the same fuse circuit.

[Iffy650]

Thanks Chris,
Indicators and brake lights are working, with tank in and earthed, still cant get the fuel gauge to work.
I put a new sender in the tank, connected it up correctly and the gauge still doesnt work.
Do you have any more suggestions?
I'm hoping its not the gauge.

[Iffy650]

Solved the problem!
The terminals in the connector at the gauge (in the back of the instrument cluster) were a bit corroded from damp.
With a gentle rubber with sandpaper and a swirt of wd40, the gauge is working.
Just got the fun of putting the fuel tank back to go this weekend.

[ChrisRLewis]

Well done for finding the fault

[andyzeetec]

Good to see you've fixed it. 

Good luck fitting the fuel tank