Assumingly, v12 has similar ‘advanced’ British technology on board like the rest of Jaguar range. Your dash light will go off when short to the ground. In 3.6 - coolant “sensor” is nothing different than metal pin located at specified height in the expansion tank. Try to drop the plug to the coolant tank itself and see if the light goes off. If not - you’re looking at frayed wires… Jaguar was doing plenty of savings on the sharp metal edges left in the final car
assembly…
That is the sensor. It’s a simple piece of metal sticking into the tank thru a rubber grommet. It basically just detects coolant by putting a small electric current thru the coolant. No current = no coolant. There is an electronic device under the dash that takes that current, and tells the light to come on or not. That device can fail. There are rebuild instructions for that device on here somewhere.
Edit: Here’s the repair instructions. https://forums.jag-lovers.com/t/low-coolant-warning-module-rkc5259-repair/359567/2
Yes I saw in the link you provided that John showed it’s there too. I’m going to get in there today to take a look.
I’m also working on a '72 E-Type and a '59 Corvette simultaneously. All 3 have been sold and I’m finishing up many issues in preparation for shipment overseas. The E-Type has been the most entertaining… er, ah, I mean frustrating. The XJS has given me some problems too but pretty much have that one ready.
When I get into the sensor issue on the XJS I’ll certainly keep this thread updated and will take some photos for future reference.
David, Actually the XJS is quite dry underneath when a car is below it. The Corvette is good too, but after I cover the XJS underneath it I put a few cardboard sheets on it just in case. My 4 post has drip trays that cover the entire opening. When the E-Type is on it they’re mandatory. lol
Good idea…I’ll check the XJS reservoir too as it may have some junk in there preventing the sensor from getting a good reading.