I did a simple mod earlier this week. I modified my corner running lights to accept a 1157 dual filament bulb. This would make the corner lens into both my running lights and my turn signals. I won't show you how to solder in this how-to but this is a process I chose to do because I know how to. You can choose crimp connectors instead. Parts I used:
1157 bulb socket, pigtail, and bulb base I cut out from a mid 90's Galant headlight. (keeping it Mitsubishi lol)
Knife, Phillips screwdriver, rotary tool, wire strippers (if available, but knife works the same), electrical tape, and extra wire to extend harness.
I was originally going to use JB Weld but I had access to a plastic welder so I used that instead.
Step 1: Remove corner light housing and bumper light housing.
Step 2: Now that you have your housing out and the bulb and wiring removed you can start to trim the plastic off to make room for the new base which I trimmed to a round shape. The hole I made was roughly about 1 5/8 but make sure the base barely fits. That way its easy to apply the JB Weld without the new base being loose and falling through.
Step 3: Plastic weld new base to housing( or use JB Weld)
There's your new base for your new 1157 bulb to twist into! Now to the wiring part!
Step 4: unwind/peel your stock wiring out to reveal bare wires for the turn signal and running lights. You'll see that the running light power wire is thinner than the power wire for the turn signal. Hard to mix those two up. The ground is obviously black. Now you will have to extend the wiring for the new pigtail so make sure to have long enough wiring to work with. Twist the new wiring together to make sure everything works before you permanently crimp it together. You should have a working running light and turn signal light working. After you test it and it's all good then crimp on the new wiring( I chose to solder and heatshrink it)
Here's a poorly drawn diagram to help, but you should have an idea of how it should be wired together. Use the ground wire that's already on the running light pigtail.
Step 5: Assemble back together and double check to see if everything works.
Sick back and admire your work!