vdo temp senders

[vennard]

Hi, I just bought a vdo temp gauge with a dipstick sender. I have an idea in the back of my mind that there is a way of wiring a sump sender into this as well to give an average temp as it is reading from the tp and bottom of the engine. I think I read it on here but ant find it in the searches. Was a long itme ago too. Anyone got a clue?

Cheers Karl