No heat

[Roger2845]

I have a 1999 xj8 sovereign and could not get any heat from the system. I found that the fuse in the auxhilliary pump circuit had blown, fuse number 10 in the engine bay. This did not solve the problem so I checked the pump was working by applying 12v directly to the pump leads whereupon there was quite a spark and the pump came alive. Still no heat so I checked the feed relay number 3 if memory serves (refer to handbook). The relay was fine so investigated further and with help from my local garage discovered the motorised water valve adjacent to the aux pump (LH bulkhead area) was siezed. A replacement was sourced from Auto Reserve for about £22 ( new jag one over £200) and fitted by my pals at the aforementioned garage. You guessed it, still no heat!
Getting a bit concerned and thinking it must be a module serving the climate control system, I dug around for more info. By chance I was chatting to a fellow member at our local monthly meeting (who has a similar xj8) and he sent me some info including some circuit diag. info.
The breakthrough came when he e-mailed me some time later and asked if I had checked fuse no. 3 ( in engine bay fuse box) and lo and behold it too was blown. It turns out this is the feed to the aux. pump relay but is not labelled as such, I believe it feeds the fog lamps.
Success, and pleased as punch, although red-faced at not checking every fuse in the box!
Apologies if this is common knowledge to all you xj8 owners, but if not I hope this helps other unsuspecting members.

[Andy P]

Hi Roger,
Thanks for the information.
Someone in the future will definitely benefit from this.
Hope you are pleased with your XJ8.
Take care.
Andy

[RichardSEL]

Only a month late, but FWIW I used to carry around this chart since my fuse box cover didn't have this chart on it.
Course since having that print in my glovebox, never had a fuse blow again, in three XJ8s later