I have no heat in my 1998 jaguar XJ
I replaced the auxiliary coolant pump and it still isn’t working. Can anyone tell me other components did they come in to play that I could replace? Many thanks to all

 

See page 51 lower left side

X300 98/E COVER (jagrepair.com)

Notice the heater valve ( water solenoid ) , this is modulated open and closed for coolant flow and can be tested with a 9 volt battery

I am assuming you checked the fuse and relay

There is a front control panel test that can give you some information

The test is on page 109

www.jagrepair.com/images/Training Guides/703_SG.pdf

The fault codes are given in a TSB that follows , the earlier X300 is the same Denso system for the X308

14-10 (jagrepair.com)

 

Thank you for this very detailed information!
Happy New Year

 

There happens to be a Youtube video of the climate control front panel test

The X300 and X308 is the same Denso manufacture for the climate control

 

Probably just needs the heater core flushed out with some white vinegar.

 

Great, now I’ll know what to expect, many thanks!
I replaced the aux coolant pump, and that didn’t help. I’m thinking o need heater core flush, but I’m having trouble finding someone that’s not “afraid” to remove the parts necessary to access the core. Do you think a “normal” system flush or two would help the issue, or does it have to be the core flush/back flush operation “

 

The flush material is available at the parts store as a small bottle

The question is if you leave the flush chemical in your coolant forever or drain you existing coolant , save it , put the flush chemical in water , let it work , drain water , put your original coolant back in

Water as the coolant of course it not a good thing but only a temporary carrier and the carrier and dissolved junk is drawn out and disposed

With the work involved with that there may be something easier to try or look at

I'm not saying in the long run a coolant flush is not a good idea

The other question is a whole coolant system flush or just the heater core / matrix like you asked

To isolate the lines and get to them for just a core flush might be a pain or it might not that others would have a suggestion

 

Edited a little bit above post

 

Okay thank you for the additional info! Good stuff here.