[T3] Fuel Gauge Grounding Solution

[Jim Adney]

This email list doesn't allow attachments, so I can't send one to the list, and 
taking photos is difficult for me, but let me try to describe this.

There is a black wire that comes out a hole in the black plastic bulb holder. 
The hole is large enough to feed a brown ground wire in.

On the front of the bulb holder there are 3 sockets that connect to 3 brass 
pins on the back of the fuel gauge. You can see that the lowest pin is 
connected directly to the case of the instrument. Look at what that lower pin 
connects to inside the bulb holder. Solder the end of the new ground wire to 
one of the places that the ground pin is connected to.

What I would supply would be a brown wire with a piggyback connector on 
one end. You would disconnect one of the ground wires from the back of the 
speedo and connect the new ground wire in its place. Then connect the 
removed wire to the piggyback connector.

On late cars, '71 and later, there may be a free ground lug on a brace near 
the steering column. In that case, just connect the new ground wire there. If 
there's no free spot, use the piggyback feature, as above.

Either way, your gas gauge instrument now has a reliable ground.

Jim


On 26 Jan 2023 at 13:04, Bryan Peters wrote:

> Can we see a picture of the connection you make?
> 
> Sent from my iPhone
> 
> > On Jan 26, 2023, at 9:20 AM, Jim Adney <jadney at vwtype3.org> wrote:
> > 
> > Over the years, many people, including myself, have noticed problems with 
> > odd behavior of the gas gauge, especially with the key off and the E-flashers 
> > working. It was pretty clear to me that this was a grounding problem, but I'd 
> > never managed to figure out a solution.
> > 
> > The problem is that the fuel gauge cluster depends on it's spring retaining 
> > clips to make a good ground to the backside of the dash. Over time, as the 
> > plastic dash pad shrinks, this connection becomes poor or nonexistant. VW 
> > should have fixed this in '69, when they added grounds to everything else, 
> > but they didn't.
> > 
> > I finally got around to looking at this situation and I see that I can add a 
> > ground wire to the bulb socket that snaps onto the back of the fuel gauge. 
> > Connecting the other end of that wire to a good ground will solve this 
> > problem.
> > 
> > This is an easy solution for '69-on Type 3s, where there are good ground 
> > connections readily available under the dash. It, or something similar, should 
> > work for earlier cars, but might require some modifying/innovation.
> > 
> > If you have good soldering skills, I can send you the wire and connector that 
> > you can solder in yourself, for $5.
> > 
> > If you prefer to mail me your bulb holder, I can add the wire and do the 
> > soldering for $10.
> > 
> > Postage increases those prices to $10 and $15, respectively, so the best 
> > thing to do, as always, would be to combine these purchases with something 
> > else you need me to do, so they can all ship together.
> > 
> > -- 
> > *******************************
> > Jim Adney, jadney at vwtype3.org
> > Madison, Wisconsin, USA
> > *******************************
> > 
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-- 
*******************************
Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
*******************************