P38 LED dash mod

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Originally Posted by marty_nz

Hi all...

Fairly new here, but a regular poster in the rr.net forum. Originally from NZ, but now live in the UK though...

Anyway - I have done pretty much the entire dash in LED's - all the fascia switches, clock, headlight switch, instrument binnacle, window switchpack, HEVAC and the rear door window switches. (I've also changed all the interior lights, but they were off-the-shelf/eBay purchases)

To do all of the rest of them I've actually put LED's and resistors in all the switches, (white for illumination, coloured for when the button is pressed).

I've also done the instrument panel, so the back of all the gauges are lit white, with blue needles. Have also done the message centre so it is completely white.

I mainly used 3mm wide angle LED's (they were advertised as 120 degree) and then scuffed the head of them lightly with fine sandpaper to further diffuse the light.

I also added a few extra LED's to the window switchpack, so the 4 way mirror control is now back-lit too (the switch has clear parts in the arrows - but LR never lit it!)

I've done the HEVAC with the same wide angle white LEDs - but it still comes out green, as the colouring is moulded into the back of the buttons :(

I know things like this are worthless without pictures... so:

Attachment 55794

Attachment 55795

Cheers,
Marty

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The cluster looks great

Good job! I'd like to understand how you changed the colour of the gauge needles? did you need to paint them separately ...do they look "blue" in daylight?

Hi,

Sorry - I forgot to hit 'subscribe' to the thread when I posted, so didn't see that you guys had replied! Apologies!

There was a fair bit of work involved in doing the conversion - but I think it is worth it for the more modern look!

The dials themselves have wide angle LED's behind them (diffused with sandpaper) to light them evenly. You have to scrape the plastic coating off the back of them to remove the green colouring. (LR had green covers on the backlight lamps, and then green plastic coating on the back of the gauges)

This is obviously a bit hair raising, as you have to do it whilst the gauges are all in one piece, and the needles are pretty fragile (and they don't come off either - they are solidly stuck onto the metal shaft of the gauge)

The needles are lit by separate LED's - they have a plastic light pipe which goes to where the factory illumination lamps are, to then direct the light onto the base of the needle, where it then illuminates the length of the needle (like crude fibre optics!)

I cut the ends off of the light pipe, and notched them big enough to put a 3mm LED in. There are 2 LED's in both the fuel gauge and the temp gauge. The main speedo/tacho gauges are lit by 2 LED's aswell - but one from either side (each effectively lighting half of the needle's travel). I have also covered the light pipes for the needles, to prevent light spillage onto the back of the dials. I originally used black PVC insulation tape, but have since opened it back up, 'tweaked' some of the LED's and also changed the PVC tape for black heat-shrink, as I found some in my box of bits that was the right size.



The needles, in daylight, are clear like they are as standard, and are then just lit when the headlight switch is turned on (as normal) except that the standard lamps/holders are removed, and the wires from the LED's are soldered onto the pads.

I am currently working on a second one, using some SMD LED's and a couple of other options for the message centre which aren't so 'invasive' (I cut a whole load of plastic out and it's lit by 5 wide angle LED's to give even coverage).

As before - pictures say it a lot better than words, so a couple more for you..

Attachment 56017
Message centre

Attachment 56018
Green coating removed from main dials

Attachment 56019
LED in the light pipe for one of the smaller gauges

Attachment 56020
The main gauges with LED's installed. I also bridged the gap between the middle 2 LED's with PVC tape, as there was a bit of light spillage onto the back of the dials.

Since doing this, I have pulled the cluster back out and tweaked a few things. as mentioned above, I've removed the PVC tape and replaced with heat-shrink. I have also tidied up a whole lot of the wiring, and moved a couple of the illumination LED's about to give a more even light across the whole cluster.

I currently have a second-hand cluster which I'm also working on, to see if I can refine it even more.

Hope this is of interest!

Apologies for the small images - I have bigger versions available - but not sure how to get them to show!

Cheers,
Marty

The pics look realy good. I am planning on replacing my speedo bulbs with LEDs (green for the information panel and blue for the rest). Can you advise how many and what size bulbs you used?

I used LED's to light the instrument cluster. The message centre needed about 5 or 6 white LED's with enough diffusion to stop there being bright spots.

The actual cluster itself needed 2 LEDs per needle to colour the needle properly, and probably 10-12 white LEDs to get an even coverage of the back of the gauges.

The new method I have uses probably 20 odd white LED's to edge light the instruments - which looks a lot nicer, and more even - and is less fiddly to do. The new method I have for the needles uses 4 SMD LEDs for each needle, but is a lot brighter than before.

I personally don't think that just replacing the current incandescent lamps with LED variants will work too well, as the LED's will probably be quite directional and give a patchy looking result.

If you do try it out, then post some photos, as I'm keen on seeing how it turns out... I could be wrong, as these days they are making LED units with chips on every side to give 360 degree covereage.

Marty