Wiring fuel gauges

[sunquest]

Cimo has partially illustrated this with an earlier post.
If you measure the resistance between S and 12v at the gauge, you may have a reading of say 140 ohms. When you link a second gauge you add another 140ohms. As they are connected in parallel, the result is 70 ohms ( See http://www.1728.com/resistrs.htm ) Therefore you need a 70 ohm resistor in series to restore the designed ohmage of 140 ohms.
I am sure someone will be able to explain this better than I. My only claim to fame was I was once a GPO yes GPO telephone engineer some 30+years ago. Geoff

 

[cimo]

But a resistor in series will not half the resistance of the senders it in effect increases the resistance of the senders. So if it works I don't how it works but will have a play next week when I an on my boat.

this is correct. I suspect the VDO range of gauges are of the single coil variety. although, again, their litrature doesn't help whatsoever in this regard. so a different solution will be required in your case Roger.

Why I am interested is I have a similar issue with my oil pressure and temp gauges/senders so if it does work I will also be a happy bunny.

More likely you will have to add resistance in parallel. If you want to, send me your measurements and other details and I will help if i can. Incidentially, the G terminal is not "Ground" but "Sender" on these VDO gauges!

sunquest - gald to hear that worked out.

rgds
c