So...all of my various gauges - gas/oil/temp even the speedometer (which had a transmitting unit replaced) seem to be somewhat intermittent. By which I mean they may, or may not, work, and there's never any assurance of accuracy.

Is this just part of the Lucas legacy, or is it something that could be improved?

 

Seems to be a fairly common problem, and often seems related to bad earth connections, either at the gauges themselves or at the big earth near the battery in the boot.

I recall a thread here talking about the exact locations of those, and will go search and see if I can find a link for you. In the meantime, I wouldn't be surprised if one of the more experienced members can tell you exactly where it is (I seem to remember mention of taking off the instrument cover and putting earth connected screws right into the backs of the panel as one possible solution, though).

 

These two threads were the ones I was mainly thinking of.

Speak to me of cleaning guage contacts and adding a ground - Jaguar Forums - Jaguar Enthusiasts Forum
My first thread Odometer,engine temp guage - Jaguar Forums - Jaguar Enthusiasts Forum

 

If you remove the instrument cluster and clean all of the connections on the rear with Isopropyl Alcohol and a cotton bud (DO NOT USE ABRASIVE), there is a black wire behind the tach remove the nuts and clean behind this (DO NOT REMOVE ALL THE NUTS AT ONCE OR THE TACH WILL FALL OUT). You can also run an additional ground wire from here to the chassis.

In the boot on the RH side of the battery is where quite a few earths are screwed to the body remove these and give them a clean here you can use fine sand paper to make sure the ground area is bare metal, also give the terminals a clean Alcohol is fine for them. Do these first they will most likely fix your problem, if not then you can go cleaning other earth terminals that are harder to get at.

 

Thank you, all! I had asked about cleaning and knew someone had mentioned grounds, but the batter info is new to me. I appreciate it!

 

Occasionally all my instruments suddenly stop working; if I stick my fingers in the fuse box under the steering wheel panel (on a right hooker V12) and waggle the fuses around the instruments come back on.