Fuel Gauge/ Temperature Gauge

[Haddock]

My Caterham temperature gauge is rather fickle in the sense it's is occasionally shows random hot and cold when running. Today both the temperature and fuel gauge continued to show a reading when the ignition was off. When turning the ignition on both needles swept the gauge as normal. 
it's a 2018 360r

Just wondered if this was a a common issue or something I should investigate further 

[Jonathan Kay]

I'd investigate further.

But I don't know how those modern ones work (the ones that do the sweep).

Have you got a multimeter? And a wiring diagram: if not let me know if you'd like one.

...

For the temperature gauge: with the ignition on what happens when you disconnect at the sender, and when you short the sender connection to earth?

Jonathan

[Jonathan Kay]

Anyone, please:

With this type of instrument is all the clever stuff inside the instrument itself? And are the electrical connections the same as on traditional instruments?

Thanks

Jonathan

[revilla]

I seem to remember (not got diagrams in front of me now) that the clever stuff is inside one of the instruments, possibly the tacho, and that then controls the others.

[Jonathan Kay]

Thanks.

Wiring up comes up through the tacho, but I can't work out if it's just a connector or adding the sweep.

It would be nice to disconnect one of the instruments, jury rig it, and see.

Haddock: This could be useful in fault-finding as it helps to identify a single point of failure for two different instruments/ circuits. Earths are common candidates for that but yours staying on when it shouldn't doesn't sound like that.

Jonathan 

[Haddock]

Thank you Jonathan and Revilla !

I can see more investigation is required . The car is still in warranty so I ll check with Caterham next  in case the gauges / wiring are covered. It's a self build but of course the gauges are pre fitted / wired by Caterham 

If it's not covered I'll make a start myself  as suggested