Hiya all!

Decided I'd register and post this swap I just made - no pictures, so 56k friendly
It all began when I grew fed up with my gas/heat gauge having no light at all, pissed me off frequently while driving when dark. I then went to my local parts store and acquired the lamps for the dashboard and changed all but the 2 ambient lights (the really tiny ones that are on the top) for i couldn't find them. For them, I ended up attaching two white LED's with their current limiting resistors for the old lamp bases after tugging the lamps out (twisted lead form the contacts)...
Time passed and an idea started to evolve - why not go all-LED? I tried my hand first with turn signal and high beam lights - all LED's mentioned here are Avago brand 5mm oval - green for turn signals and blue for high beam. As current limiting resistors I used 560ohm for greens and 750ohm for the blue. I cut the positive leg of off the led from under the stopper and soldered a resistor onto that stump of a leg, then modelled the whole thing so that I could solder it to the lamp base and tried. It worked out nicely, and because there was some height left, I could twith the led a bit to point the light to wanted direction. Then the rest... All them red signal lamps changed to red LED's in similar fashion with 560ohm resistor (red-orange avago Y VA - dunno if those markings mean anything to any of you, but it's color and brightness) and for choke the yellow Y4VA with 560ohm resistor too.

Then I had to remove the gauges totally and try to model the arcs so that I could place LED's in proper place on speedometer and gas/heat-meter. I had to remove some material from the gauge base to get some clearance.
I consulted this very from on how to remove the gauge face from speedometer, for it was the trickiest one - I drew the arc and marked the speeds on translucent paper, then transferred the said drawing onto some thin palstic we had lying around where I work - it's easy to work on, about the same thickness as a credit card and cut the shape - odometer pin! Damn thing wouldn't fit, so I had the cut a wedge for it, trying to retain the uppermost speeds intact... Finally the shape was set and I could start poking more blue leds I heated up the legs, one LED at a time on a candle flame, then simply pushed the LED trough the plastic all the way to the stoppers, and here I failed a bit: I placed the leds so that the leads were along the radius, not along the circumference - the latter would allow up/down positioning a lot easier for left/right was quite accurate. I ended up with a fitting arc studded with 20 leds, positive and negative leads alternating. I flipped the thing over and divvyed them into six groups of three and one group consisting of two. Then I bent the leads so that I could solder them, left side leds negative bent to parallel with centermost leds positive, centermost leds negative bent to meet rightmosts positive, leaving two legs pointing up. After that, I soldered 100ohm resistors to those positive leads pointing upwards. For the serries of two, it's simpler - negative to positive and that's it, leaves two leads up. 270ohm for the positive lead. Then I "gathered" the negatives of the three last groups of three, those that were supposed to light 110 km/h to 200 km/h, with a length of wire, and also the positives too, from the open ends of the resistors. Repeated to the upper 3 groups (30-100 km/h) and similarly for the group of two (0-20 km/h) an placed the arc on it's place, drawing the wires out of the lamp socket holes - and soldered them to now empty sockets - leaving enough wire to be able to flip the arc over if need be. Then I fixed it into position with some minor drops of hot glue - icky stuff - and let it cool. Then to the gas/heat gauge - similarly made shape and clearance, used 9 LED's. You guessed right - three series of three LED's, for easiness sake, four per arc and one in the middle. Attached this on the base with hot glue, so that the uppermost leds are a wee bit below than turn signal's point. Reassembled them gauges and went to test - on the speedo I had one series blank, I had soldered ground wire to wrong position... that's what you get when you're doing stuff around 10PM after waking up at 6AM... fixed it quickly, leaving the gauges on place, but unscrewed. On european models the left side cable takes care of the dashlights, so I attached only that cable, turned on the lights and went to finetuning the leds, so that they all shone nicely on the gauge faces, and then reassembled the whole thing.

Why did I do that? Why not, when I had enough blue leds 32 in total, plus 5 oranges and one yellow - and few days well spent.
Better approach would have been to print the gauge faces and device the shapes from there on - making better fitting pieces...

Questions, remark, anything is welcome. I may take some pictures in case there's enough interest, they do clarify things a bit.

 

oh, forgot to mention http://ledcalc.com/ - a great aid on calculating the current limiting resistors, also tells the whole circuits total current consumption.

 

comig up. prolly next week or so, a writeup on detail - changing the cluster to one with tacho, lighting with leds and with dimmer. Detail!

 

Sounds good, I'd like to see some pictures of it.

 

This took totally another direction. Swapped the cluster to one with a tacho, and redid everything. This time I've got a dimmer attached... PCB-layout will be available too incase anyone is interested. I'll try and finish the writeup in a week or so. (Minor slowdown, my wife delivered a healthy boy)

 

x2

 

yes this seems like a really good post i would like to sse it too

 

x3

 

I still need a few more pics - one of the backside of the LED-array, to show how they were connected together, and few of it when it's alight. Pretty hectic time back at work and home, so please be patient.

 

pics wud help, son

 

Linky Work in progress, still missing stuff from there.

 

 

Updated with the dimmer layout.

 

can you post some pics of it.... lit up ?