Well, assembling parts to continue refreshing the interior of my 98. I've done the console armrest cover...have the leatherique dye for the seats to freshen them up when the weather is nicer (it's currently 20 degrees F here in the midatlantic), and just received a replacement instrument cluster from the west coast.

1. Disassembled the rear, removed the circuit board (I have a static-proof surface and the necessary tools, so...why not). Will test all the lights to see which ones need replacing before reassembly.

2. Removed the front bezel; while the clear plastic was not cracked, there were multiple rub marks on the front face. How to repair? Well, I have a bottle of Honda Glare Professional Polish which I've used, successfully, over the past decade to clean up marks on my scoot windscreen(s), helmet face shields, watch faces, electronic meter covers...what could possibly go wrong?

Nothing. Using a microfiber towel, continued to buff the clear plastic in, initially a circular motion lightly to spread the polish (it has a decreasing 'grit' as you work it), then across the rub marks, finishing up with a light side-to-side application, then buffed off with a fresh microfiber towel. I concentrated on the clear sections that were outlined by the gauges...and I have to say that the results were outstanding.

3. Removed the 4 screws attaching the front to the cluster body, and, with a soft (like feather soft) brush, cleaned off the face of the gauges (being careful to NOT break the stop pins at the low end of the gauge needle travel. These are not d'Arsonval meter movements; they are run by stepper motors attached to the meter faceplate. Neat. Reattached the front bezel to the instrument assembly. Admired the work.

4. Placing the assembly on a soft mat, removed the 6 screws holding the rear cover to the assembly. Unplugged (by using a small common screwdriver between the cover and the end of the connector and gently levering the connector up) the 4 ribbon connectors: 1 for the tach, one for the speedo, and two for the fuel and temp gauges. At the bottom, is a red connector which is the data input to the MFD at the bottom of the speedo. That pulls out, and by gently lifting from both sides of the circuit board, you can release it from the case.

5. Looking at the various ICs, I'm thinking that the mileometer/odometer information is kept in memory on the main circuit board; the IC which is located at the bottom of the case between the main circuit board and the MFD is an Oki M6665xx chip, which is called out by datasheet as a display driver. Since the purpose of this effort is to fix the delaminating MFD display that is currently in the car...I'm thinking that in order to maintain the mileage I currently have on the car, it will be a matter of swapping main boards (assuming the above, and the connectors, etc are the same) with the newly cleaned and polished instrument display. Am I along the right line here (assuming that issues I've read both here and elsewhere would seem to indicate that the car wants to see the modules that it was programmed with?)?

6. So, need to hie myself down to the auto parts store and pick up some #194 bulbs to replace the big backlighting ones (the others are fine; they aren't used as much nor are on constantly, so, their life is a lot longer), and wait for decent weather to pull the cluster out of the car and do the swap, all things being equal.

(Sorry for no photos...will take them and show all the ash and trash when I do the next one...)

 

I also have a 98' XJR and in #5 you posted about a delaminating MFD. If your talking about the digital readout of the pack, I'm not sure if it's possible to swap another one into the board and still have the exact mileage readout. On the top left of my digital readout, you can see that it's separating a little. It's like it's glued together. I have a spare pack but from a 99' XJ8. I looked into doing what your wanting to do but I think it's meant to not be messed with for tampering with miles. Do you have any other thoughts on what might be done to successfully swap the two boards over?

 

I swapped my main gauge cluster (from miles to kilometer reading), but kept the little digital readout.
In my case the ODO was stored in this little unit.
That all for a 98 4L N/A.

However, as each solution has a problem, I assisted one of our Italian forum members, and on his newer car (around 2001 if I remember well), this trick did not work, and it seemed the ODO was stored in the main cluster (or a combination of things and places).

Maybe, and really just a guess, Jaguar modified things when moving to the AJ27 engine, and you might not be able to swap the little board.

It is not a whole lot of work though, so you can try and see.

 

Not really a lot of work, as you say, mostly swapping in and out boards. Don't want to get into a situation where the car becomes inoperable when the ECU sees that the cluster is different and refuses to do anything. As far as I can tell, and I may be wrong, the only thing on that small board is the display driver chip (the one I mentioned above) and a few SMD resistors (which I'm assuming are used to pull the data and display lines), and the display itself is an 80x20 pixel display array, so, maybe, just maybe, it will work.

Easy to swap around (5 connectors and 6 screws), so, perhaps this weekend when the weather is supposed to be warmer than polar vortex. I'd do it tomorrow when the forecast is for it to be 60 outside, but, unfortunately, I'll be in North Carolina for a 90-minute sales call so...will have to wait a couple days. Not like the car (or the spare cluster) is going anywhere in the interim. But, like most folks, if I see a potential solution or fix, I'm anxious to try and solve the problem.

 

No other thoughts other than to try it and see what the result is. Just like 'faint heart n'er won fair lady', success can only be won if you try understanding that failure, in this case, is a possible outcome.

 

I did notice the stepper motors as well, though more due to hearing them than pulling the cluster apart. Not that they're very loud, but with how quiet the car is designed to be they can be noticeable. I think one of the motors is the cause of a "tickdown" noise I've been getting on gentle deceleration. Fairly minor concern for now compared to a lot of other things..

Fun fact, the '98 clusters have differently shaped ticks for the speedo and tach, and the tach gets ticks at 200 rpm intervals while 99 and later tachs get them at 500 rpm intervals. That's the only difference I know between them unfortunately, can't say much more... Oh wait, some of the later AJ27 tachs got the XK faceplate, don't remember what MY, which has a template which includes the adaptive cruise control light. The x308 never got this feature, so the light is defunct, but it can be seen from light spilling over from the amber/red status indicators under the speedo, esp at the startup check. I don't know if electronics changed then, or between AJ26/AJ27, or whenever..

There's some documents highlighting technical changes for each model year in the large files section. While I doubt they'd be that in depth, they might come in handy..

 

You need to make sure the replacement cluster is compatible with your car by comparing it to the VCATS list in the boot.
If it doesn't match the cluster won't work and the massage "INCORRECT PART FITTED" will be displayed. There are also different connectors for them for post 2000 cars.

The cluster is east to get apart as you say, just have to know what areas to be careful with. I didn't use a bench or table to dismantle it though when I did it to clean and replace a broken airbag light bulb. I just used the lid of the wheelie bin as it was a nice summers day.

 

where in the boot is the VCATS list?

 

See pic, the silver label is the VCATS list (seen here while I was removing the spaghetti from the previous owner).

 

Yeah, I checked and the vcats is the same....just want to keep the mileage where it belongs whilst fixing the MFD display screen. It's a bit warmer here today...heading out to pull the head and swap things around and see.

 

Sometimes you just have to go with your gut. So, since it is warm enough outside to work...figured in between teleconferences for work, I'd tackle handling the cluster repair.

1. Disconnected the battery.

2. Pulled the cluster fascia panel (put your hands at 9'o'clock in the tach opening gripping the outside circumference of the hole and your other hand at 3 o'clock on the opposite side and give a quick tug. It's wood veneer on a metal backing. It comes right out; one or two of the clips may stay in the plastic trim...either leave them there or pull them out and reinstall on fascia panel. I've never bothered and never had a problem reinstalling, so YMMV.)

3. Put a dab of butyl windshield tape (I do restore cars that use it, so I have it in the shop) on the tip of a philips head (yes, I know the screws are whitworth, but they're not torqued in, just running in plastic) and removed the 4 screws to release the cluster trim. The butyl tape is real sticky, so, the screws just stay on the tip as you remove them.) Remove the plugs from the back of the fog light switch on the left and trip computer button assembly on the right, and gently push the connectors back through the trim.

4. Unplugged the two connectors at the bottom. The earlier connectors (for this MY) have two tabs, one at the top, one at the bottom. Just squeeze and the plug can be removed.

5. Dismounted the cluster from the car and retired to the bench.

6. Removed the 4 torx screws from the front and the 6 from the rear. Disconnected the orange connector at the bottom that goes to the display driver for the MFD, and the 4 connectors at the top for the gauges. Gently released the display driver board at the bottom from it's two locating ****, and lifted the old face out.

7. Took the replacement, good face panel (btw, the pn and rev levels were the same on both cluster parts tags, so...figured it was a good omen) with the working display and assembled it into the ORIGINAL (remember, the goal here was to preserve the mileometer/odometer reading) cluster frame, and reassembled it all. Took the new bulbs that I had picked up a couple days ago and replaced (why not? It's out, I have new replacements, will save having to pull this again soon) the 4 #194 backlights.

7a. I'm going to make an assumption, at least for this model, and probably applicable to more than just this, but my assumption is to just compare like to like since that's all I've had to work with, that the mileage value is stored on the 'motherboard' for the cluster that is mounted in the white case of the cluster to which all the gauges and lights are attached. That small board on the bottom of the display, on the orange circuit board that is fed by the orange connector, is solely a display driver based on its OKI part number and lack of other ancillary chips other than resistors on that board, and does not retain, other than the embedded character generator and necessary electronic drivers for the MFD, the mileage reading of the car. So, while you end up having to buy a complete working cluster to replace something like a dodgy display or futzed up gauge...if (and only IF) the original working motherboard is 1) same vcats number and the same or earlier revision than the second hand replacement...you SHOULD be ok in either swapping the original motherboard into the replacement case, or swapping the replacement face onto the existing original motherboard. Make sense? No guarantees, see:

http://www.lotuseuropa.us/disclaimer.htm

8. Reinstalled in the dash, reconnected the connectors to the display, reconnected the fog light and trip computer switches, and reconnected the battery. (i.e. assembly is the reverse of disassembly.)

9. Turned on the key...and was rewarded with a working display, system check note (driver door open, which it was), and the mileage as it was this morning before I started. Started the car...tach came up, gas needle worked, and temp gauge started its movement. Backed out of the drive...and around the block...and the speedo worked. Cycled the display button through all the displays...and everything works.

10. Popped the fascia panel back on. Job done. Celebrated with a fresh cuppa. The only change I can see is that the km/hr gradations on the new display are every 20 km/hr vs the 30 km/hr of the original...ie 20-40-60-etc vs 20-50-80-etc. I can live with that.

Photos below:


Old display with the delaminating LCD.


Ta-Da. Working display and gauges.


Mileage was saved! No need to explain to the next owner...


And, apparently, the new backlighting bulbs are just fine.

So...all in all, a fix that took, all in, about 30 minutes (and that didn't include rousting up the screwdriver, butyl tape, and blanket (to cover the dash to check the lights...). Easy peasy.

 

See the lights on illuminated , mine has stopped working, I have had the cluster out to replace a large bulb, but didn't see anywhere to replace a bulb.
Has anyone got a photo of the cluster apart or where to replace ? I would appreciate this greatly
Cheers Geoff

 

You have to dismantle the gauges as described in this thread. I've added a link to my own renovation thread where I have a photo and description of the bulb(s) you're needing to access.
https://www.jaguarforums.com/forum/x...vation-166459/