Problem with VDO fuel gauge/sender

[mcvw]

Hi,

I have a VDO fuel gauge (the black round type - "cockpit series" I think?) and sender fitted to my *cough* 67 beetle, and over the weekend it developed a fault and now the gauge reads FULL all the time.

Well, not all the time... The needle only goes to FULL when the ignition is on. When the ignition is off the needle returns to below EMPTY.

I checked the fuse and that's ok. I thought it might be a bad earth, but all earth wires "appear" to be ok.

I even took the sender out of the tank and moved it up and down (with the ignition on) but it made no difference.

Anyone have any ideas what the problem (and resolution) might be?

Cheers,


Mike
PS: I know this is a Beetle related question and shouldn't really be posted to an early bay forum - but you're all such helpful chaps here - and I do own an early bay too

 

[currylager]

What does the gauge read with the ignition on and the sender disconnected?

 

[Araon]

That sounds like the wire to sender is shorting to earth, if you have a continuity tester shoul be easy otherwise hand trace it back...

 

[mcvw]

I'll perform suggested checks later tonight. Had planned to do yesterday evening but a few beers after work turned into an all nighter

Result: falling asleep on train and waking up at Basingstoke!! Good job there was a train going back else it would've been an expensive cab fare!!

 

[Araon]

Yes must admit if I were to fall asleep on the train I wake up in the depot I know a couple of guys its happened to :lol:

 

[mcvw]

Hi,

With the ignition on, and the sender disconnected the gauge reads FULL.

I haven't got a cont' tester - but I have checked that all wires (from & to the gauge & fuses etc) are firmly in place.

Cheers,


Mike

 

[Araon]

You've definately got a short somewhere possibly at the dash pod- you have two connectors with fibre insulators check the condition of those (aahhh bug- trying to think now and i cant remember if its the same/similar set up). But the fact thats its registering full will indicate a return path to earth through the meter so thats yer problem either within the meter or the wire to the sender or the sender potentiometer is short (already discounted).
1 disconnect the wire to the sender at the meter whats it showing then short that meter connection to the chassis.
2 crack the meter open and visually check for short cct.
3 hand trace the wire "again" paying particular attention to areas where it crosses panel joints etc...