Hi guys, So, I thought for sure the low coolant light was from a bad sensor so I bought an aftermarket reservoir from SNG Barratt. But, it still lights up (after the engine warmed up and I was out of the driveway). Don't see any leaks on the ground. What else could be causing the light to come on?

 

Few things you could try:

1. Unplug it and the light should go out. If so, it's a sensor problem. If not, it's a car problem.
2. Put a meter across the terminals of the sensor plug. Should be closed circuit with the empty tank in normal position and open circuit if the tank is inverted (i.e float down and float up positions).

 

SNG Barratt have apparently been sending out some 'new' tanks with non-functional sensors: see https://www.jaguarforums.com/forum/x...sensor-212425/

Maybe worth considering if that is your problem.

 

Happened to me also. The little magnet in the float has fallen out of the float and is laying on the bottom of the tank. When I bought my car this was the condition and someone had just cut the wire to the sensor and shorted the two wires together. No morning light and nor more low coolant warning either. I bought a new tank and replaced the old one. Problem solved.

 

Yes, that was my original post. I'm suppposed to get a replacement tank/sensor today and I will test as well. Wonder if they are getting some bad batches? It seems to appear that way.

To test the light you have to make a jumper wire and short the wire harness to the car.

 

I replaced mine last summer and I get an occasional low fluid warning even though it is full.
wj

 

Thanks! I will try your suggested diagnostics.

 

I got my new replacement coolant tank from SNG in today. I made a quick video of testing the continuity of the float sensor: https://youtu.be/OpHmNNEMfNU