basic sockets and screwdrivers
needle nose pliers
set of two spoons
magnifying glass (optional)
hot-air reflow station (optional)
tape (electrical and/or masking)
flux core solder
resistors (we used 470ohm 1/2 watt)
LEDs (we used 5mm, 7000mcd, 3.3-3.6v, 25mA)
Step 1 - Dash Removal
- Lower the adjustable steering wheel and, with the key in the ignition and the emergency brake engaged, put the shifter into drive 1.
- Remove dash shroud and remove bolts holding in the gauge cluster.
- Disconnect the bus connector from the back of the gauge cluster
- Press the tabs and remove the clear cover to the gauges.
- Mark needle placement with tape so that upon reassembly the needles are in their original location.
- Remove gauge needles with even pressure, spoons are awesome.
- Remove gauge face carefully, it is plastic and discolors upon bending.
- Press the remaining tabs, to remove the back of the gauge cluster and remove the gauge circuit board.
- Plug the circuit board back into the dash and turn on all available lights and indicators.
- Use a multimeter to identify hot and ground leads on each lamp, MARK APPROPRIATELY with a permanent marker. These lamps are each in a different orientation.
- Unplug and remove the gauge circuit board from the dash.
- Remove each of the lamps with a hot tool of your choice, apply heat and use pliers or tweezers to gently pull on the lamp.
- Be careful not to leave the soldering iron or hot air on a single trace for too long as it may cause damage to the circuit board itself.
- Take the long lead (anode/positive) on the LED and bend it facing straight up.
- Snip the long lead at about the top of the LED.
- Tin the snipped LED lead with solder.
- On the resistor bend a lead down and snip it at about the length of the resistor.
- Tin the snipped resistor lead with solder.
- Join the two tinned leads together with a brief touch of the soldering iron.
- Bend the remaining leads in towards each other and snip them so that each lead has a 3-5mm inward facing leg and a 3-5mm gap between them.
- Tin each of the solder pads on the gauge circuit board with a small bead of solder.
- Using tweezers or a pair of pliers hold each set of LED-resistor combos in place with the resistor lead on the positive (hot) pad on the board.
- Quickly solder each lead in place with the iron, this should take less than two seconds per lead. Note that leaving the iron in place too long can damage the led, resistor, surrounding components, and even the circuit board itself.
- Ensure the LEDs are facing upwards to avoid 'hot spots' within the lighting of the dash.
- Plug the gauge circuit board back into the dash and ensure all indicators light up properly.
If any LEDs do not light up, disconnect the board and:
- First ensure each lead is securely soldered onto the appropriate pad.
- Check to make sure none of the pads have been inadvertently joined with stray solder - a magnifying glass is wonderful.
- Ensure proper polarity with multimeter with the board plugged in, make sure you have the right pads identified
- After ensuring all LEDs are properly operating disconnect the board.
- Carefully place the circuit board on the back plate.
- Ensure that the new LEDs are not obstructing the top plate and put the two halves together and snap in place.
- Lay the gauge back display back on to the cluster.
- Carefully place the gauge needles back on to their appropriate gauge with even pressure.
- Replace the cluster glass and ensure all of the gauge cluster snaps are fully engaged.
- Reconnect the gauge assembly bus to the back of the assembly.
- Ensure all lights still light up.
- Screw the assembly back in place with the originally removed bolts.
- Replace the dash shroud.
- Enjoy your newly lit dash.
Sources and Additional Information:
http://www.duramaxforum.com/forum/how-tos-diy-write-ups/50520-how-leds-gauge-cluster.html - this was the original idea.
http://www.garrettgalloway.com/index.php?p=projects&e=4 - site with additional related projects and more images of this project.