Last week all the lights on my main instrument cluster went out, today I noticed the speedometer gauge is not working. I could not find the fuse that feeds the lights or the speedometer. Anyone know which fuse it is, (not listed in owners Manual) or is it possible the cluster went bad? Has this happened to anyone else?
Thanks
Tony
2004 XK8. Pacific Blue
102000 miles

 

I would first check the two connectors that go to the displays. These are the only way power and data goes in and out .
remove the kick panel below the steering wheel then the wood surround and then you see the connectors left and right .
for information you need to access youtube series "To the Garage "

 

I always see the advice to disconnect the battery when connecting/disconnecting those two connectors. Is that good advice or an essential action?

 

That is essential advice. There is a good chance of blowing the cluster without disconnecting the battery first.

Check fuses first though. Cluster fuses are in the driver side, end of the dashboard fusebox, Fuse #14 and Fuse #18. You will need a bright light on the fusebox to see the embossed fuse numbers on the black plastic rails.

 

Thank you. I have some lamps to change.

 

I have taken mine out 4 or 5 times just turning off the ignition without any problems but disconnecting the battery will not hurt.

 

I assume the risk relates to a light being on and causing a spike in the power which screws the control module. I'm guessing that pulling fuses is too complicated in comparison to disconnecting the battery.

I'm a little reluctant to disconnect the battery as things will be forgotten like the modules that learn your driving pattern etc. Windows and codes I'm not so bothered by.

 

Disconnect the battery!
No 2 ways about it...

In these cars the Main Instrument Cluster is involved across many many and multiple systems. Dis-connect the battery!

 

Thanks I ordered new lamps, I might as well have them handy for when I open things. I’ll update whenI access things,
Tony

 

Speedometer is working again, did not do anything. Go figure. Waiting on lamps
patience right!

 

Sometimes the treat of ripping things apart is enough to smarten the car up.

 

Hmm... Anyone here will tell ya,,, I'm not the most thorough or meticulous - in this case I would keep digging. It's probably something simple (or not)...

I say that because MUCH is involved with that cluster. Much. Then, they are expensive and an electrical glitch could render it a paper weight.

Disconnect the battery, pull out and inspect all of the fuses on both the RH and LH door jams. Remove the cover (carefully) of the cluster itself, throw the latches and re-latch the wire harnesses on both sides a few times. Remove them and inspect for corrosion. Look for water sign on both fuse panels and in the area, maybe even behind and on top O the cluster...

jus say'n... It's not a part to be fooling with.

 

Re: the battery thing to disconnect or not. Obviously the safest thing is always to disconnect the battery. Virtually everything in the workshop manual had "disconnect the battery" as the first step. That being said I have done the instrument cluster bulbs a few times and NEVER disconnected the battery without any problems. Guess I like living on the edge.

 

Personally, I have been convinced that disconnecting the battery is the right way to go, enough very experienced members have said it's the wisest thing to do.

Added to which a friend who did IT hardware support for years and he dis/reconnected hard drives many, many times with no problem and then one day he fried the controller when reconnecting. Not quite the same thing but close enough.

 

Another vote for disconnecting the battery as step #1 before doing any work on the car beyond oil and filter changes.

Modern life is scary enough without tempting fate.


Z

 

I received my lamps, changed all of them, this was quite the process. On the 04 XK8 I had to remove the bottom panel(screws) both panels on the steering column, the vent cover on the left of steering wheel(Left hand drive version) then the glass on speedometer, then the speedometer. Easy access to the lamps. I then put it back together, total time 1 hr 15 min.
And no lights still! Fuses good. Ordered a dimming switch. Will replace that. Yes I’m guessing now. That is the only component that controls the lights I’m assuming.
Did not disconnect battery since I did not disconnect the instrument cluster cables (2 ea, one on either side.)

 

Well…..I replaced the dimmer switch, still no lights in the instrument cluster, The console does dim however, it did with both dimmers, I’m assuming then that the dimmer is getting power due to this. Any ideas. I have an electrical schematic, but. I really dont i
understand how to read it and what voltages to check for at the terminals.
suggestions are appreciated

 

Tony, I'm better at electronics than mechanical. I am looking at the 1998 electronics manual.

Confirm no lights major instrument panel (speedo, tach, dash stuff in front of driver) this is fed by connector FC25

Confirm no lights on minor instrument panel (voltage, oil, stuff in center panel, fuel, coolant temp) connector FC26

Whats strange is vehicle speed is on FC26, you say thats ok now right?

T. Confirm that all readings are being shown all guages. This is only about illumination.

This will help me focus 4u.

John

 

Hi John. Only illumination all gauges working. I installed Led lamps I dont think they are polarity sensitive, besides what are the odds all the lamps installed the same polarity

thanks you in advance.
Tony

 

Need to check for voltage FC25 - 27. That means fascia connector 25 (big 48 pin) pin 27 which is connected to Red Orange wire. That's the incoming illumination supply from dimmer module.

My assumption its 12volts.

See picture its the 3rd slot in from left bottom row.

Look these are 1998 documents. Can you compare to yours?

Tony, its late, working from small phone, please give me feedback. Make sense? Questions?

John