1995 3000GT VR-4: Headlight Popup Switch Installation

• Why Do I Want To Do This?

  • If you need a switch to control a device you added to your car and you want to keep the OEM look, this modification is for you. The OEM popup switch is a DPST switch where all 3 terminals are unconnected in the '94+ cars.
  • I used this switch to provide the lighting signal to all of my aftermarket devices. Many of the electronic devices I have installed in my car have an input for an illumination wire; this wire lets the device know when the car's headlights are on, and the device dims its lighting for nighttime operation. I found that the nighttime lighting mode of my aftermarket electronics made it difficult to read them at dusk or when driving with my headlights on during the day. Thus, I wanted a way to interrupt the illumination signal to the aftermarket devices if I wanted to. Essentially, I wanted to be able to have my headlights on and have my aftermarket electronics operate at full brightness. This switch allows me to do this.




• How Long Will It Take Me To Do This?

  • Plan on an hour or two so you're not hurried.




• Anything I Should Do Prior To Attempting This Procedure?

  • You may want to remove the plastic cover for the steering column to give you some extra room to maneuver. There are 4 screws on the bottom, some clips in the middle, and then it just pops off in upper and lower halves.




• What Mitsubishi Parts Will I Need?

  • (1) MB604770 ($35.00) Headlight Popup Combination Switch (from '91-'93 models)




• What Other Parts Will I Need?

  • Misc 18ga wire
  • Solder
  • [optional] T-taps and quick-disconnect connectors




• Where Can I Get the Stuff To Do This?

  	Part	Company/Contact	Part Number
  	Headlight Popup Combination Switch (from '91-'93 models)	Mike Deal at Rockville Mitsubishi	MB604770
  	Misc. 18ga wire	McMaster-Carr
  	T-taps and quick-disconnect connectors	McMaster-Carr
  	Solder	Radio Shack





• What Tools May/Will I Need?

  • #2 Philips Screwdriver
  • Large Slotted Screwdriver
  • Soldering Iron
  • Pliers




• Erik's Review

  • I'm completely happy with this modification and I've had zero issues with it since installation. I really like being able to adjust the brightness of my instrumentation when the car's lights are on. I also really like having the OEM switch, even if it's not labeled correctly, as it doesn't stand out from the rest of the interior.

The Procedure

	Remove Inner Trim Screws
	There are two Philips screws on the underside of the inner black plastic cover that surrounds the gauge cluster. Remove them so you can remove the black trim.
	Carefully Pry Instrument Cluster Trim Out
	There are little spring clips on each side of the trim, so carefully pry the black trim away from the dash. You may want to use a slotted screwdriver or a small prybar for this.
	Disconnect Trim Panel Switches' Wiring Harnesses
	Disconnect the wiring harnesses for the switches attached to the trim panel so that you can completely remove the trim panel from the car. If you have small fingers and small tools, you may not need to remove the trim from the car as it may difficult to maneuver to clear the steering wheel.
	Examine The Trim Panel
	Note the screws that attach the switches to the trim panel. You'll need to remove the screws for the left-hand switch so you can replace it with the new switch assembly.
	[optional] Remove Instrument Cluster
	If you have anything that you need to do with the instrument cluster, now would be the time to do it since it's so accessible. Examples would includes aftermarket gauge faces and replacing burnt-out lightbulbs.
	Compare Old And New Switches
	Here are the two versions of the switches. They have the same wiring harness connection and the same mounting points.
	Connect Wires to Popup Light Switch Terminals
	Pins 8, 9, and 10 are the connections for the popup light switch. I chose to use pins 8 and 10 for my connections. That way, the pins are connected when the button is in the depressed ("on") position and the pins are disconnected when the button is in the the "off" position. I soldered the wires directly to the pins and then pushed the wires through the empty holes in the OEM harness. I then secured the wires with some electrical tape. I attached the other end of the red wire (pin 8) to the illumination positive wire (pin 3) with a t-tap and a quick disconnect connector. The way the circuit now works is that when the popup switch is closed, pin 10 (green wire) is connected to pin 8 (red wire) which is always connected to pin 3 (illumination +). When the switch is open, pin 10 (green wire) is not connected to anything.
	Extend Wiring As Necessary
	Here is the final circuit - the green wire shown will be routed through the dash to the area behind the radio for connection to the "illumination" input of all of my aftermarket instrumentation.
	Button Everything Back Up
	Reattach the trim panel and route the wiring as necesary. Now I have an extra switch on my instrument cluster that controls whether my gauges operate in night or day mode when my headlights are on. When the headlights are off, the instrumentation always uses the "day" (bright) illumination.