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Discussion Starter #1 (Edited)
Hi,
I recently repaired my middle brake light myself after finding too high a price from wrecking yards and the dealership. Costing me about AU$15-20 (US$10-15) to do. No soldering required. More efficient than stock middle brake light - milliamp current draw reduced by at least 85%.

Items:
  • 12 x 5MM LED RED RND CLEAR 7150mcd (SKU: 7383/R7C3-ARUB/P/MS)
    Minimum voltage rating 1.8v (What I recommend). Can be substituted with White Clear LEDs of at least 4kmcd (4000 mcd) rating with Forward Voltage (which means minimum voltage) 1.8v to 2.0v. I purchased 20 LEDs,since they are so cheap and in case I broke during repair.
  • Heatshrink & lighter (Optional, could cover the exposed wires with glue instead)
  • 1x 30ml Selleys Multigrip glue
  • 1x 100 Ohm (R100) 5 watt ceramic resistor (Alternative compatible resistor configs suggested in photos)
  • Some copper wire and scissors to cut away insulation
First step involved glueing the LEDs into the reflector housing. Waiting about 3 hours before it had dried enough to continue connecting the LEDs up. I had to add some glue into the holes allowing them time to firm up, to narrow them down as the LEDs had tendency to fall through. The LED bulb does not have to be seated perfectly straight inside the reflector housing socket.

Red LEDs are better to use. White ones have 2/3rd of their light blocked by the red visor. Do not use other colours as you will get little to next to no light.

This is what we call in Australia a "bodgy". A highly improvised repair that looks like it would not work, but it does 馃槄

Glue takes 12 hours to set properly, always apply and dry in well ventilated area.

Setup uses two groups of leds each with 6 bulbs connected in series. This has one downside, if a LED fails the whole group of leds will stop working. Alternatively you could wire the leds all in parallel and use a 47 or 68 Ohm resistor and in this way a failed LED does not affect another.

If using other LEDs you must ensure the nominal milliamp draw is not exceeded, as this increases failure rates of the LEDs. Milliamp draw in LEDs does not scale linearly like in a resistor. 0.1v can drastically increase current consumption.

You can use a LED resistor calculator like this:-

In the case of LEDs in series, add the Forward Voltage of the LEDs up for example if 1.8v, the new forward voltage is 10.8v then enter the number of parallel, series wired LED groups, in my case two.

You can get the LED specs by entering the SKU into google, or possibly the vendors website.
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Photo taken when car not started. Middle brake light LEDs brighten a bit up more with engine running.
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Discussion Starter #3
Wow! That's a lot of information! But it does look great! By the way, did you price a new lamp assembly?
Wrecking yard wanted aus$65 from an old car that has sit in the sun for years and had to wait a couple days for it to be available as they have to find the car and remove it. Holden are asking hundreds of dollars, I came across a thread somewhere but cannot remember the specifics and a video on Youtube mentioned US$200 to get a new lamp and have it installed by the dealer. I looked at the pcb of the original and got the impression it was designed to fail. This setup is simple and ensures all limits are stayed within. Could be improved with an inline fuse, voltage clamp diode in parallel with the 12v rail to soak up transient spikes etc. If it fails ill report back here.
 
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