I have a Jaguar xk8 01 and finally figured out the issue which was the alternator and the previous owner wiring in the wrong one. It was under powering the electronics as a result as well.

It still charged the battery and such but the electronic when driving has obvious problems but while I was driving.. since it's my only car at the moment.. I turned on the heat and it would only work for 3 seconds ans then get cold. Fan motors in all are working yes

Mind you it's 30° outside. I've checked the hoses, it has correct coolant and coolant levels are good, thermostat was changed to the metal design, so as the water pump. Both hoses are of course hot and going through the radiator and fully pressurized and does not collapse when off. But no heat.

Not sure if it's the fault of the alternator/electrical issue during the car running. Any thoughts?

Also pulled codes from the check engine the alternator also caused, and one is for low circuitry to a few electronics. And I know these cars are sensitive which is why I'm asking specifically our community.

 

Sounds more like the heater coolant pump?

 

If alternator warning light is acting normally and not glowing when it should be off then the alternator is fine.
The water pump takes supply via relay in engine fuse box check if it is drawing current. Access is 100 % crap ...I fitted a new on behind the expansion tank ..there is an article on how to do it on here by me ..Bosch pump is much cheaper.
check also the solenoid valve which when disconnected allows flow to the heater.
I was never able to see the original pump from above or below so good luck.

 

My apologies, I should have also stayed yes the battery light is on, which is how I know it's the alternator along with the odd sounds it's producing

 

Thanks, I'll keep this as notes for when I replace the alternator.

 

If light is on and its wired correctly then alternator is faulty but you do seem to have a record of not getting your wiring right. Check for +12 at the bolt terminal and that you have the connector correct.

 

If you're referring to my previous posts about the alternator I didn't wire that, it was the previous owner.

I'm trying to reverse all the issues going on with the car and so far I've fixed most of them including the chair issues and the rear tail light assembly, glove box, antenna, rear side markers, replaced battery etc.

Just haven't gotten to the hood yet as it's been too cold to take the car apart for 5 hours to change the alternator and properly joint the correct wires to a new head for the new denso alternator.

The alternator they fitted was from a junkyard that was already bad and making noise, and ontop of that the guy wired it like it was a house light switch.

 

Update: Eventually after a while the heat started to work again, may have been a clog of some sort. High rpm's saved the system. And the alternator was replaced