Oh bang

There's a typo. first block should be all related to sensor1 and the other to sensor 2.

"total fuel resistance =[(Resistance1-Pad resistance1)+(Resistance2-Pad resistance2)]/2"

Now a example of first pic.

R=[(114-1)+(287-0)]/2

R=[113+287]/2

R=400/2

R=200

Golfi_vend: OK, the plot thickens (as they say in who-done-it novels) It's starting to make sense-thanks for the clarification.

Galvanised into action by your new formula (and my curiosity) I've produced the table below which to my (very) untrained eyes seems to confirm what the measuring blocks are saying.

Let me explain how the table works: The alpha letters in the first of the table relate to the alpha letters that I have pasted in each of the measuring blocks in the RT screen. The first column in the table refers to the pics in your post #5 with the first pic being "1" and so on.

I've simply transposed each of the values in your 4 x pics into the table as per the above protocol. The values in the last column have been calculated using your revised formula.

As you can see, each of the calculated values in the last column is within a "bee's dick" (forgive the Aussie vernacular - I couldn't resist!) of the measuring block value for the "Fuel Sender Resistance". Do you know what level of accuracy is normally required for these senders? Without wishing to demean the quality of VW's sensors, the set-up for resistance mechanism of the slider in your photographs doesn't give the impression that the sender is a precision item. So I'm guessing that the accuracy of the "Total Fuel Resistance" is OK to a whole number (i.e. no decimal points)- does this seem reasonable to you?

What is also clear from the table is that there is a negative relationship between "Fuel Sender Resistance" and the "Fuel Level" (i.e. the slope of the equation that joins the two variables is negative). If I had more rows in the table it would be interesting to guess at an actual equation but I have no idea whether the relationship is logarithmic, linear, exponential, polynomial etc. Do you know this relationship?

A couple of other matter's to which I would value your comments. Clearly the "Fuel Gauge 2 Resistance" is pivotal to getting the calculation correct. But this resistor doesn't seem to be an active component (i.e. it doesn't change). Is this just a fixed resistor?. But the most intriguing conundrum in the sender topology must surely be the form of your revised equation. Why is it so? The formula suggests a pair of resistors that are connected in series with the "Pad" resistors somehow negating their value - odd concept! And why divide by two?

Anyhow, interesting stuff, Ive learned alot - Thanks again for sharing this matter