Rob,
The resistance of the sender ranges from around 80 ohms at the full end down
to about 6 ohms or so when empty. (My Smiths Test Box gives 79.8 ohms at F
and 5.9 ohms at E). So you can see that if the T terminal is shorted to
ground the gauge will read Empty or a bit less and if the T is open circuit
(infinitively large resistance) the gauge will read more than Full. It’s
counter intuitive, I know, but that really is the way it works. It’s a
classic fault with this type of gauge but is usually caused by an open
circuit sender rather than a broken wire. Nick has already changed the
sender but that doesn’t mean the new sender is above suspicion. Some repros
are notoriously badly made and it’s a good plan to check with a multimeter
before fitting.
Eric-----Original Message-----
From: owner-xk@jag-lovers.org [mailto:owner-xk@jag-lovers.org] On Behalf Of
Rob Reilly
Sent: 29 September 2015 20:45
To: xk@jag-lovers.org
Subject: RE: [xk] Xk petrol gauge again
In reply to a message from Eric Capron sent Tue 29 Sep 2015:
If the gauge is always reading full, I’m thinking its not a break, its a
short to ground (earth) with the green/black wire.
Try removing the green/black wire from the sender and isolating the end so
it doesn’t touch ground. Now with the key on, the gauge needle should read
empty. If it reads full you have a short to ground somewhere in that wire.
Touch the wire end to a good ground and the needle should jump to full. If
it doesn’t you have a break somewhere in that wire.
XK120 FHC, Mark V saloon, XJ12L Series II, S-Type 3.0 --Posted using
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