Unexpected issue with swapping the instrument pack on a P38

Hi all,

I'm new here and have a question to ask. I'm a refugee from another forum where the sole advice was "use the search function" before even reading the OP's question or even knowing if the question had been answered previously so I'm hoping for better luck here.

My car is a 1997 P38 DSE and over the years the LCD on the instrument pack had died from too much exposure to the sun. The HEVAC display passed away some years ago and I replaced it.

I am in Malaysia where we have the speedometer showing km/h and the instrument pack has the part number AMR5991.

I bought a used instrument pack on ebay with the original intention of cannibalising it for its LCD. This came from a UK car which had its dial showing mph and km/h inset (part number AMR5989).

When I got my own instrument pack out of my car, I found it to be in such a dire condition- and in any event I couldn't find any information on how to remove the LCD module from it- so now I'm contemplating swapping the entire instrument pack over.

Now...... I know when I do this I will get an "Odometer Error" warning because of the differing mileages on the new instrument pack (160+k MILES) and on my BECM (409k KM). I also know that it is possible to sync the odometer to the BECM with my Faultmate MSV-2 (my most often-used tool on this car, more than my screwdrivers and spanners) whereupon the BECM and Odometer will agree to use the higher of the two mileages recorded, which is fine by me.

Here are the questions:-

Is it safe to sync an MPH instrument pack with a BECM that had been dealing with a KM/H instrument pack since birth?

Also, is it safe to sync the BECM with an instrument pack bearing a different part number from the instrument pack it replaces?

Finally..... is there anywhere I can find instructions on just transplanting the LCD from the one instrument pack to another instrument pack as per my original plan? I have the RAVE CD and it goes as far as removing and replacing the instrument pack but doesn't go into the innards of the thing.

Thanks in advance!

Rave was written with main dealer fitters in mind,if its broken change like for like no need for expertise or thought. Sorry I cannot help,@Rick-the-Pick may know I've tagged him.Welcome

Cheers mate.... any and all help most welcome!

Have you checked Youtube for howto videos?...

Strangely akspeedo has a fix and a video for the L322 binnacle but nothing for the P38(!)

Actually there's so much information on how to fix the L322 binnacle LCD I'm beginning to wonder if I should buy one myself!

I would imagine it will just take the higher number from your BECM. I have a vague memory of someone fitting a binnacle from a continental car and it overwrote his BECM milage with the binnacle km reading - gave him quite a shock!

@martyuk might know but he's working away and might not be able to respond for a while.

Aaah.. now that's a useful memory. I'm fine with that because I want to keep the (correct) BECM reading which at 409k km is a much higher number than the 160+k miles the odometer currently shows.

Thanks for that! Ok... score one for a straight swap. One more and I'll go for it!

If youve nothing to lose, you've everything to gain

That's what I thought as I reached for the faultmate a couple nights ago...... and then realised the depth of the poop I'd be in if I messed up the BECM doing it.

So back went the faultmate in its bag and I went on the internet in search of a forum..... and found this one!

Data’s handy with a Faultmate msv2. May respond to a PM?

Data? Ok thanks- I'll go look for him!

What forum where you on?

Grrrrrr said:

I would imagine it will just take the higher number from your BECM. I have a vague memory of someone fitting a binnacle from a continental car and it overwrote his BECM milage with the binnacle km reading - gave him quite a shock!

@martyuk might know but he's working away and might not be able to respond for a while.

Click to expand...

You might like a second opinion. My memory isn't the most reliable. Rick or Marty are the experts.

Mark Piercy said:

What forum where you on?

Click to expand...

Rangerovers.net

It really was a great place for a very long time but I guess change happens and that's just the way things are.

Grrrrrr said:

You might like a second opinion. My memory isn't the most reliable. Rick or Marty are the experts.

Click to expand...

Heh.... well sure, but still thanks for that. I hope Rick, Marty and Data will weigh in soon. I can still read my binnacle LCD at night so it's not like I can't use the car for fear of running the oil sump dry or anything.

If you can read the dash at night that points to the back light bulbs being knackerd.

It isn't just a need to replace the globes in the instrument pack is it? The "LCD" screen is powered by three 2W globes which take a few minutes to sort out.

We have had people on here before that weren't aware of the dimmer switch!

Actually I've already had it apart and the cause is both polarising films burnt to a crisp. The bulbs are just fine. Maybe one day I'll have a go at replacing the polarising films but from what I can see, it's going to be fiddly in the extreme. The display needs to be powered up and displaying something while I try to figure out the correct orientation for the films. That's after I figure out how to disassemble the LCD module so that I can clean the bit of the films that have fused to the panel.

One day... but that's not today. I just want to get it running with one binnacle- whether mine with the good display off the mph one, or the mph one itself.

Sorry - As Grrrrr mentioned I am away again (and not on this forum very often either).

Instrument clusters....
I believe that the cluster holds the mileage in either kms of miles - so just swapping the cluster - whilst the numbers being right, might do some weird conversion... I'm really not sure as I've unfortunately never had a mph and kph cluster on the bench together to see what they do. It might change the consumption/range in the trip computer to mpg etc if you put the UK cluster in...

However.... to answer a couple of other questions... I don't see a problem pairing different part number cluster with BECM - it's all talking over the same serial link, so I don't think the protocol changed at all on that over the P38 MY - so that should be fine...

Regarding swapping the screen though - it can be done - but be aware that the really early clusters had a bigger screen and won't fit in the later plastic housings, and vice versa. BUT you could just carefully swap parts over and it would work.

To get to the LCD screen, take the back plastic cover off the PCB. You'll need to unclip it and disconnect the speaker from the board (it's got a connector).
Next, sit the cluster, face down on a nice thick towel or bubble wrap to protect the front plastic from getting scratched. On the PCB on the back towards the bottom/centre/right there's a ribbon cable plugged in - carefully disconnect that (it's the LCD screen cable).
Then undo the 12 screws in the kinda 'v' pattern that hold the gauges in. They'll still be held in place by the front covers etc.

You can then lift the PCB up, and disconnect the white connector which is towards the left on the underside of the PCB.

With the PCB removed, I usually loosely screw on of the screws back into each gauge to stop them falling out with you take the front covers off. BE VERY CAREFUL NOT TO OVERTIGHTEN THESE SCREWS AS IT WILL BREAK THE FINE WIRES THAT ACTUALLY DRIVE THE GAUGES.

With one screw in each gauge, remove the front clear and black plastic covers which are clipped onto the cluster. Then remove the faceplate from the front of the gauges.

Then carefully undo the screw from each gauge in turn and remove them. You should be able to now see the assembly for the LCD screen clipped in and unclip it, remove, and swap it over with your donor one.

IF the donor one IS different, then what you can do is put your original gauges into the white plastic shell from the cluster with the good LCD, put one screw in to hold them, then refit the face panel and black/clear covers. Then flip it over and remove the screws, and then refit your PCB (plugging in the connector under it!). Then re-screw the gauges in AGAIN CAREFULLY SO AS NOT TO OVERTIGHTEN/DAMAGE THEM (I put that in caps as one I LED converted the DIY installer of it damaged all the gauges... but as long as you're not a gorilla with them and just very gently nip them up, then it's really fine).

Plug in the ribbon cable for the LCD and then put the back plastic cover on, plug speaker in and done.... your gauges/pcb/mileage but either with a new screen in your casing, or you bits in the other casing with a working screen.

Hope this helps..
Marty