When Dave finished the refurbishment of his fuel tank he found that the fuel gauge no longer worked.
Dave wrote to Rob about checking the instrument cluster end -
The other little problem has to do with the fuel gauge. I removed the mechanism, of course, when I refurbished the tank, and I was sure I labeled the wires correctly -- but now the needle is pegged all the way to the right (past full) no matter what the level in the tank is. Do you think I may have crossed the wires, or is it possibly more than that? I hope not, as any problem with the mechanism will require yet another removal of the fuel tank.
Rob responded -
The wire from the tank mechanism goes to the "trembler" box on the speedo, and this connects directly with the needle (I think it's a direct connection - or very short wire anyway), and the needle is earthed through the shell of the speedo (should be a brown earthing wire connected to the speedo case somewhere.
Dave wrote -
Also last night we finally pulled the instrument cluster out -- and found nothing wrong. The yellow wire from the fuel sensor is firmly attached on the one side, and two black wires which I assume are the power leads on the other. It's never as easy as you hope it's going to be, is it!
Rob responded -
So that indicates that it may be the needle mechanism itself. I've never heard of one blowing, but I'm sure it's possible. You should be able to test it by "hotwiring" it to 12v and see if it moves.
Dave was not able to complete the repair of the fuel gauge system before his son took the car away to college. His son had occasion to take the car into a VW shop, where the mechanic fixed the fuel gauge system. Having check all of the wiring, Dave assumes that the problem was in the fuel gauge sending unit. You will note the added emphasis on careful handling of this unit in the Fuel Tank Removal and Refurbishment procedure.
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Last revised 5 May 2004.