I just repaired a heater hose leak on my 1999 Jaguar XJR and the sensor light on the dash was working before the repair. Now the warning light telling me that the fluid level is low is staying on all the time. Does anyone know what might be my problem. I have checked all wiring connections and they are ok and the fluid level is full in the expansion tank. Thanks

 

The float in the reservoir sunk and is stuck to the bottom, thats assuming of course that it isnt actually low. You can try to lift it up and unstick it, if not you need to replace the reservoir

 

In the small tank where you add fluid, there is a float inside that is moving and not stuck however I see no electric wires attaching to the tank which makes me think I am looking in the wrong place. There is a switch below the tank that two hoses attaches too but I think this is the thermostat that opens once the temperature reaches operating temperature. The low fluid light is still on. Any help would be greatly appreciated.

 

ml500, if you can see the float move, then that essentially confirms a bad sensor. The only other possible issue is a wiring problem and that could be caused by getting the wire pinched between 2 points. But, 99% of the time, it is a bad sensor. Replace the sensor and then go from there.

Granted, because you were under the hood recently to fix the hose, you may want to look at the connection to the sensor to make sure that it is pushed all the way on to the sensor. It is possible that as you were moving things around, you knocked a plug loose.