After hours of searching for this mod was only able to find it on two websites, none of which were this one. Fullsizechevy.com and Dieselplace.com where the only ones I could find.
It all started with the whole speedo stepper motor and since my truck isn’t covered due to the 86k miles on it, and I didn’t want to pay the 425 bucks the local dealership wanted I decided to change the motor myself.
Being the preventive maintenance kind of guy I figured it would be a good idea to change out all six. That turned out to be way easier than I could have hope and save myself a lot of beer money.
During the motor replacement process I notice the several gauge lights that were burnt and decided it would be a good idea to make those into LEDs. But, since those are regular 12v incandescent bulbs I knew I had quite the task ahead of me. So after hours of research and refreshing my mind about LEDs and resisters (it has been 5 years since my last electronics class) I felt confident enough to do it.
I order my LEDs from superbrightleds.com. They have a plethora of different bulbs to choose from. I chose the Super White LED 5mm, 4500mlm, with a 360 degree viewing angle. The huge viewing angle reduced any chance of hot spots on the gauges. They cost a little more but are worth it. Just ask the guy on fullsizechevy write up.
Since the incoming voltage is 12v resisters are needed to drop the voltage to the three volts the LEDs need to operate or they make smoke….trust me on this one.
Instead of using math I just used a calculator on the internet to find my resistor values. With my 9 lights at 3.3 volts 20ma and I used 14.4 as my voltage just to be safe; I came up with ½ watt 560 ohm resisters. So I just ran to my local Radio Shack and got 15 of them for less than 3 bucks. Spares are always handy to have.
Weller 25watt Soldering Iron
Very small rosin core solder, I used .022" I got at Radio Shack
Small side cutters
Small gauge wire stripper
9 volt battery
Pieces of small wire, i used a chunk of CAT 5 I had lying around
A. Cluster Removal
NOTE: READ Whole article before starting, especially final assembly section
Sorry no pictures, but its fairly simple and straight forward.
1. Remove dash trim piece, mine pops right off since it has been off so many times.
2. Remove four screws 8mm I do believe
3. Put gear selector all the way down. CAUTION vehicle will roll if on a slope
4. Pull out cluster part way, reach back and squeeze blue thing on the harness and gently wiggle back and forth. There is a lot of pins there so be careful.
5. Once harness is off the cluster will come out with a little maneuvering.
You are able to drive your vehicle with the cluster out. You just don’t have any vitals. I drove mine to work for a week without any problems. I do have a Scan Gauge so that gave me my important info. As long as I didn’t run out of fuel I was fine.
B. Cluster Disassembly
I would suggest a well lit clean workbench. (Living room coffee table in my case)
Sorry no pictures again but not too hard.
1. Basic physics tells me that plastic is brittle when it’s cold. So if your cluster is cold like mine was (negative temps in Southwest Montana) I would suggest letting in warm up to room temp.
2. Remove front black bezel. There are clips on the top and bottom that attach to the white center piece. A flat screwdriver and some gentle massaging it all it takes.
3. Removing Needles. A regular kitchen fork worked the best for me. Just insert and gently pry up.
4. The back piece comes of easier than the front, just a few more clips
5.Then the rest pretty much falls apart after that.
C. Removing Bulbs
Using my soldering iron I just hit them for a few seconds right next to the little blue cradles that hold the bulbs. There are four solder spots for each bulb but only two are holding the bulbs in. Once you get each corner they pop right off.
Once the bulb where removed I wanted to be sure which of the connections were my positive 12v and negative ground. So plugged just the circuit board back in (blue clip on harness facing down) and using a 12v test light I just checked each bulb location for my positive 12 volts and put a small dot next to it with my Sharpie.
I cut each resister down on one end and soldered that straight up to the positive connection for each bulb. Then I bent each of the bulb leads to fit properly next to the resistor while keeping them as low as possible. Remember LEDs are polarity sensitive. So it is important that they are installed on the correct positive and negative terminals for them to work.
Notice resistors and sharpie marks
Notice Positve and Negative
Once they are all soldered in I put the white plastic piece on top to be sure they weren’t too tall.
To test them I soldered some wire onto the terminals where the bulb for the trans temp would go (I don’t have a trans temp gauge) and hooked up a 9v battery to it. And to my surprise they lit right up.
Then I took it out to my truck just to double check and made sure they still worked properly. They are even dimmable.
D. Final Assembly
Put everything back together as you took it apart but leave the needles and front cover off.
This is where it gets tricky. Somehow you need to be able to put the needles back into there correct location. I am lucky enough to have ScanGauge so I was able to set all my needles back except the Oil pressure and Fuel level. For the oil pressure I warmed up my truck to operating temperature and marked where the needle was. For the fuel level I just filled up my tank when I was done and put the need on the full mark. For everything else that’s up to you. I would suggest using a GPS to set your speedo and checking your idle rpms before you remove the dash and then you can just set it back with the vehicle idling. My was right around 900rpm. The voltmeter should be around 14.5 or so when idling and the temp gauge around 190 when completely warmed up.
1. Soldering iron is HOT and you will melt things you shouldn't, so watch were you are putting it
2. Always make sure any pieces of wire are not touching parts they shouldn't be.
3. Make sure you clip off any excess of the wire that were soldered.
4. Before testing with power, shake the crap of the assembley so any pieces of solder or wire are out of there.
5. Don't blame me for anything you did wrong, this is just a guide, I am not resposible if you fry your guage cluster. If you don't feel comfortable doing it then you problably shouldn't.
I'll have final installed pics posted shortly.
Any questions or constructive criticism are appreciated.