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Old Jan 31st, 2019, 17:42   #6
Laird Scooby
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Last Online: Today 20:03
Join Date: May 2012
Location: Lakenheath
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Thanks Bob - thought i was right on the Yazaki/VDO differences. Nice to have it confirmed though!

Onto the sender unit, there are three wires accessible on a 3-pole multiplug under the left hand boot cubby-hole cover. There are red and brown, +12v for the pump and earth respectively. There is also a pink wire, i can't remember if it's pink on the sender side of the plug or the car side - doesn't matter as long as you can find the pink one and then unplug the 3-pole multiplug.

Connect a 22 ohme resistor between the "pink" one and brown, switch the ignition on and the gauge should crawl up to zero ish.

Now remove the 22 ohm wire it in series with a 270 ohm resistor and fit that accross the pink and brown, the gauge should move fairly quickly to full ish.

These are approximate values to test the gauge (and obviously the wiring in between), if memory serves the exact values are 20 ohms and 290 ohms but they are close enough for all practical testing purposes.

Most likely cause is the gauge though, they have a nasty habit of failing and/or developing the work ethics of a 1970s coal miner - in other words they're on strike 90% of the time but work ok when they're not! My 760 fuel gauge is like that but isn't even that accurate when it does work! I suspect its sender came from a 760 saloon with the extra sender unit in the auxiliary tank behind the seats.
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Dave

Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........
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