The bulbs behind my Tachometer burned out a while ago and I decided I would replace them with LEDs. I also replaced the ones behind the speedometer as well. Overall I probably spent more on this project than normal, but I bought a few miscellaneous items. My car is a 1992 Nissan Pick-up.
NOTE: This may or may not work for you. But it doesn't hurt to look and see if you really want to do it.
-Standard Phillips Screwdriver
-Precision Screwdriver Set
-Vise Grip Pliers*
-4 Ultra High Brightness White (Or color of your choice) LEDs. These can be swapped for almost anything really. The brighter the better though.
-Resistors. Varies based on LEDs.
EDIT: Sorry for not having any before pictures. I took it apart before I knew I could replace them and then I just wanted to get it done.
Step 1: Disassemble!
My favorite part! I love taking things apart. I apologize for not having any pictures, but every car is different. I also disconnected a few things to make the back of the instrument panel easier to access.
Step 2: Locate the lights.
I located the bulbs that burned out as well as the ones that were still good. I could have replaced more than what I did, but these are used most often. I analyzed how they worked and where power was coming from. They have two metal pieces that touch the copper of the circuit board on either sides of the holes that send power to the bulbs.
Step 3: Test for voltage.
This step requires a multimeter. When I first did it I tested with my car off and got 11.78 volts. I tested with my car on and got 13.69 volts. I decided to round up and use 14 volts as my base. I only tested with it off, because I didn't think about testing with it on until ten minutes later. Would have been bad if I didn't test with it on.