The impeller on the pump is driven by a magnetic connection to the pump shaft it is not a direct drive. Repairing the pump is often just cleaning it and or replacing the brushes.

Gus
www.jagrepair.com

 

So I attempted to free the stuck impeller first by forcing water into the outlet hose (no change) then reversing the power leads (instantly fried the pump, it is now open circuit) so kids, don't try that one at home!
As it is clear it all has to come out now, I am looking at alternative parts. The Bosch pump used on BMWs looks almost identical and costs well under $100 new, and the Themotion valve operates identically (with the additional feature of feedback) and looks like it would fit in more easily.
Not purist, I know... but possible better.
Thoughts?

 

That is not a good situation. I had removed my pump and replaced the brushes not a difficult job. I do not know what failed when you reversed the polarity on the pump but it would be worth taking it out and make a few tests. I did look on ebay and found a few used available.

Also found the pump on Amazon.

 

Member RaceDiagnostics has documented the removal of the heater pump & brush replacement here:
https://www.jaguarforum.com/showthread.php?t=61521

The component marked 'E1' in blue is a diode of some description that may have been killed by the reverse polarity.

 

Good point on the diode, it looks to be used for current steering, pretty much acts as a fuse to make sure it only turns in one direction. With the size of those windings it is not likely they fried so quickly. When brushes get worn in one direction they can bind when turned the other way, as I have rebuilt many motors I should have known better!