Just wanted to mention the pump is in fact a BOSCH product and is compatible with several other cars, including Volkswagen, Mercedes, Audi
and the Jaguar.
It's a BOSCH 0392 020 071 // 12V water pump
FORD's specific BOSCH number ends in -071 and -039 is also compatible.
(
http://lmgtfy.com/?q=BOSCH+#:+0+392+020+071 )
For your 04 LS =
http://deneau.info/ls/s6x~us~en~file=s6x33002.htm~gen~ref.htm
Item # 21 P/N 18D794 :: Auxiliary coolant flow pump.
Here is the Auxiliary coolant flow pump for a 1st GEN. (p/n 1W4Z-18D473-AA)
http://www.lincolnvscadillac.com/fo...p-Re-OEM-Auxiliary-Coolant-Flow-Pump-GEN-1-V8
:: Ironically if you open two separate windows, search for both 01 & 04 HVAC Water Pumps, you may take notice it illustrates the same P/N 18D473, yet for the
1st GEN you get to pay $197.03 for it and for the
2nd GEN you can have it for $172.85
Take note how it's also the same pump used here on the Jaguar forum,
http://www.jaguarforums.com/forum/x...iliary-coolant-pump-bosch-part-number-110805/ (see close up pic of Ford P/N)
http://www.jaguarforums.com/forum/x...-try-chemical-flush-heater-core-108987/page2/
~ Disclaimer: Double check everything, I've been wrong plenty before!!!
To fully learn if it's not functioning, you can carefully grab a hold of it while the car is idling, should feel it vibrating.
If you have no or little heat from the interior dash vents at idle and it does give lots of heat at higher RPM's,
it
is then in fact a defective Auxiliary Coolant Flow Pump.
GLWR