Dashboard display

[wyrwoc]

I am having a problem with the dashboard display (Clock, Petrol etc) located between the dials in front of the driver in my 2007 Jaguar XK.
When I first start driving the display is very dull and only just readable. It takes up to 1/2 hour to gradually light up to full intensity. It’s quicker if I have used the car recently.
Has anyone had this problem? Is there a solution?
Thanks,
Roger.

[Astromorg]

First thought is that there must be a voltage problem, either generally throughout the car's systems or a more local problem within the instrument panel.

Can you give some details about how long the car may have been standing before these occasions requiring 1/2 hour's running to self-correct and whether during that time any form of battery charging was carried out?
Did the car start without difficulty?
Have you a meter with which you could measure battery voltage at the battery terminals:
a) One morning after the car has stood shut down and locked all night
b) Immediately after starting the car and while the problem is evident
c) When the engine is running but after the problem has self corrected

Is the illumination level of the panel adjustable, as for instance you would turn it down for some night driving? If so, the fault might be related to that.

[wyrwoc]

Thanks for your reply.
I am fairly sure it’s not an overall voltage problem. The battery was new last year and kept on a conditioner if the car in not used for a while. The car starts instantly.
There is a dimmer for the dials and settings for the central Sat Nav display but they do not change this display.

[Astromorg]

If not the battery, it might still be the alternator/charging circuit being a bit slow out of the blocks. Voltage readings at different points and times should help in identifying a possible source. I just feel you have to be certain that the fundamentals are sound before getting into more detail.
At the more awkward end of the possibilities, the instrument panel itself might be faulty, but there'd need to be some solid evidence before going too far inside that?

[wyrwoc]

I will try to take some voltage readings as proposed.
Does anyone know if this display is illuminated by a bulb or led and is it replaceable.
If not what’s involved to replace the display and is it all part of the dial assembly or a separate unit.
Has anyone else experienced this?
Thanks,
Roger.

[mike020150]

This isn't a common fault. Jaguar only sells the complete instrument pack which includes the display between the dials. Dependent upon version (there are many), it's priced between £800 and £1275 + VAT. Jaguar doesn't list bulbs for the pack which suggests it's illuminated by LEDs. Consequently, it would make sense to eliminate other issues before considering replacing the pack, new or second hand or finding someone willing to repair it. Such faults can be as simple as a poor electrical connection. Breaking, cleaning and re-making a connection may be sufficient to correct the problem. However, starting with voltage tests has to be the way to go. Mike.

[wyrwoc]

As proposed by Astromorg I have taken some voltage readings.
After the car has been left for two days I took it for a two hour run today.
The display was still dull at start-up but not was bad as when it has been left for a week or more. The problem appears to improve with more frequent use.
The voltage readings across the battery were as follows:
1) 12.03 volts (Pre start)
2) 13.76 volts (Start of run, Engine running, display dull)
3) 13.56 volts (End of Run, Engine running, display bright)
Looks about right to me?
Unless there is an led that can be changed, or there are anymore ideas, it looks like I will have live with the problem. I am unwilling to spend £1k+ to replace the whole dial assembly.
Thanks everyone for your help.
Roger.

[Astromorg]

Interesting! The charging voltages are probably OK although a little lower than I would expect from my XK8, but the initial battery voltage of 12.03 is way too low in the given circumstances. Assuming it was fully charged two days ago, because when not running, the battery was connected to a conditioner, it should not drop that much in two days! I would have expected about 12.6 - 12.4v

Either the battery is failing (despite its age!) or there is an excessive parasitic current draw when the car is standing. Whether this situation is anything to do with the dim display, I really don't know, but it's probably more important to clarify and resolve than the display!

How do you feel about connecting your meter up as an ammeter at the battery?

[wyrwoc]

I have bought a new. Multimeter and remeasured the battery voltages.
Without the engine running it’s 12.25 volts and with the engine running its 14.32 volts.
My conclusion is that the problem is with the display and unless someone can confirm there is an led that can be replaced I will have to live with it. Roger.