Relighting A Gauge Cluster

When a few lights in the dashboard of  [Garrett]’s truck burned out, he was looking at a hefty repair bill. The repair shop would have to replace the huge PCB to change a few soldered light bulbs, so he was looking at a $500 repair bill. Lighting up a LED is everyone’s first project, so [Garrett] decided to change out the bulbs with LEDs and save a few dollars.

The repair was very simple – after removing the dials and needles, [Garrett] found a huge PCB with a few burnt out bulbs on board. He took a multimeter to each bulb’s solder pad and replaced each one with an LED and resistor. The finished project looks like it came out of a factory and is a huge improvement over the ugly amber bulbs originally found in his truck.  [Garrett] also posted a nice Instructable of his build showing the nicely soldered lamp replacements.

36 thoughts on “Relighting A Gauge Cluster

  1. I’ve been doing this for decades. A lot of the GM’s have dropping resistors for the heated elements in the fluorescent screens. The resistors get hot, and the solder eventually fails – The resistors fall right off the PCB. Easy fix for something that an online shop charges hundreds to fix.

  2. Also, I must say, changing the bulbs out with LED’s is not going to look good. The light diffusers in that dash depend on standard bulbs, LED’s are going to leave some areas dimly light while others are brighter than normal – This will end up looking horrible. Also, the dimming feature most likely will no longer correlate to the dimming level of other lights on the dash…

    Better to just replace with regular bulbs. They should last 10 years.

    1. The simple fix to that, is to either grind down the tip or cut off the tip of the led. Then use a file to keep the surface flat yet opaque. I’ve done this on several vehicles, including a complete LED retrofit to 2 different 2004 corvettes.

      1. Even if you do this, putting it on a dim setting will reveal that the lighting is inconsistent across the cluster…. This is also a LOT more work than just swapping in some cheap bulbs that will last another ~10 years (the aftermarket bulbs seem to last twice as long as the factory bulbs… Interesting.). The only time I would do this is when using the original bulbs is not possible due to cost or availability.

        1. Obviously, you should just replace them all so that the lighting is consistent. Why wouldn’t you do that anyway? If half of the incandescents have already failed, I wouldn’t do all this work and leave the remaining ones in there. I’ve done this, and it turned out great.

  3. I did this on a similar project but not automotive and used rgb led’s and put in a dial in to change the colors and using the existing dimmer to control pwm instead. Less power, better looking and overall just a better way to do things. Nothing like a dim green or blue dash while night driving.

    1. Actually, Amber/Red is the best night color. Your eyes have to adjust to the brightness from the gauge cluster to outside light levels. Red is the easiest for your eye to adjust to. Brighter colors can cause a couple seconds of night blindness.

      Think of it as the same thing as someone using high beams on you at night.

  4. I had to change 2 bulbs in my heater panel too.. In Renault Thalia (Clio Symbol), it’s really very simple.

    But I think conventional bulbs are better because they provide more even illumination. You can clearly see the spikes of light in his photos. Mine is pretty much evened out. I found that only things they use LEDs for are the indicators inside buttons (because they only illuminate a small dot anyway, probably)

    1. I wonder if the result would have been better had he used LEDs with a different kind of lens. We got LED christmas lights this year, and the lens is actually concave–er, more accurately, it looks the same as if someone took a countersink bit to the end of the lens. This gives pretty decent omnidirectional illumination. I’m sure you could do the same with a regular 5mm LED–chuck it up in a drill press/lathe and use a countersink bit to get the right light distribution.

      Or, he could have used surface-mount LEDs, since that’s how the original bulbs were mounted anyway.

      1. It’s unfortunately not that simple. LEDs have their shape partially for efficiency reasons. The light source itself is omni directional, but it’s encased in a solid mould. Total internal reflection becomes critical to extracting efficiency out of an LED.

        When it comes to modifying and LED you may reduce it’s efficiency as light is reflected back. That may also change it’s thermal characteristics and make thermal runaway closer than the spec sheet says.

        Just something to remember if you want to actually try this and intend to run the LED at max current afterwards.

      1. Yes, but often times older vehicles have user-replacable parts. My 1996 F150 has all the bulbs socketed. Pop open the dash, and slam in a new bulb.

        BTW, if anyone has a 1996 F150 or similar, go over the solder joints in the dash computer if it’s going out all the time. They had a cold solder joint from the factory and it’s a common issue.

  5. Most of the photos for some reason WAY over-exaggerate the ‘hot spots’ in the dash. We have since removed the dash again and filed tip of the leds a bit and it added quite a bit of diffusion and they are only noticeable if you are looking for them at this point. One other thing I am thinking about trying is some SMD leds, these should be further away from the built in diffuser behind the gauges and allow a more even appearance.

    1. Any discoveries with filing the LEDs down? Sounds interesting and useful. Just read an article a few days ago about the epoxy body inclusion lens design and the shape of the die cup…thinking about experimenting with this, but would be interested in what you found.

      1. It actually helps it quite a bit. I will try to get some more pics up soon with the modified LEDs. It will be a few days before I get them as my friend with the good camera is out of town. Pics from my cell phone don’t even show the ‘hot spots’ to begin with. I think the fact he was using some extra polarization lens attachments (i’m NOT a photography guy) made the hot spots more apparent in the pics I uploaded.

    2. Garrett, you are likely on the right track with SMDs. I’ve torn apart an instrument cluster from a piece of farm equipment that appears to have been made by the exact same manufacturer as GM used… same color board, same needle actuators…

      Instead of bulbs, it did have SMD LEDs, but they used light pipes to spread the light into the gauge. The clear plastic behind the gauge face would funnel down to each LED, usually two per gauge. I’ll double check tonight, but I think I already threw away the assembly, otherwise I’ll try and get photos for you.

  6. If only more everyday things were designed with easy repairs/replacements in mind instead of lower cost or planned obsolescence. The instrument panel should be able to fold forward and the lamps should be no more difficult to change than any household light bulb. (Not that the lamps will need to be changed that often during the lifetime of a vehicle, but still…)

  7. The “ugly amber bulbs” are amber for a reason. They’re easier on the eyes and don’t effect your night vision. Your pupils dilate or open up when it’s dark to let in more light and make it easier to see, they constrict when it’s bright. If you use blue LEDs and they’re too bright, they’ll cause your pupils to constrict when you look at them, then when you look out onto the dark road your pupils will have to adjust again, back and forth, possibly causing eye strain.

  8. I did something similar once on the car from automotive hell -the Peugeot 405. I used christmas light bulbs, rated at 12v. Worked like a charm, no polarity issues, plenty (dimmable) light. Extremely cheap too. No popped bulbs with a revved engine, so 13.8V was within the tolerance of the bulbs.

  9. Another good trick to diffuse LEDs is to take the thin plastic diffuser sheets out of an old LCD panel and trim them to shape. Make sure to keep them in proper order, and they will produce a very smooth even light.

    1. Actually it works better than the original. I did this with my own car a while back. The dimmer worked perfectly.

      I bought 10mm blue LEDs and replaced the amber incandescent lights with them. The dash looked way better, it was easier to see, less distracting to the eye at night. The dimmer worked perfectly.

  10. My first though was put in new regular bulbs already, and then I read the instructable. SOB this is planned obsolescence to an extreme. A burned out bulb is a failure mode to replace the entire assembly, the chickenshits. A need to remove gauge needles, and peel off the dial face to get to the factory installed bulb. Then you have to unsolder the bulb.I think because the blue part looks like it could be a socket, is it or part of the bulb itself? Even if it is a socket, the bulb isn’t readily replaceable. I’d illuminate the panel from the front before going to this extreme, but we are still screwed if critical warning bulb fails.

    1. Welcome to the world of American designed cars… Reasonable life of a bulb for a US car maybe half that of a Japanese or EU car… As long as the unions have a strangle hold on the US car makers, they won’t be able to afford to truly compete with Jap/EU car makers. They can make something that *looks* as nice, but get in it and drive… You will instantly know the difference. I used to be all about American cars…. I have since stopped buying our junk and putting my money into a more “stable investment”.

  11. Be CAREFUL on some vehicles pulling the dials can ruin the cluster. There are delicate plastic gears in some of the gauge pods that will be destroyed when tampered with. Like some of the previous comments if it has a user serviceable bulb…
    otherwise be gentle or you could be spending for a replacement…

  12. At a pc repair shop I was brought the cluster from a 90’s GM car that had half of its lights out(they ere led’s.. go go US auto maker sourcing!). Le swap, and good to go.

    Lately I’ve been replacing small incandecents on old BMW on board computer light boarbs with leds. You can actually read them in the day now! On yeah, it also saves about 98.50. -Seriously, bmw wants $100 for a white plastic reflector housing and a small pcb with two bulbs

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