Found this on eBay for a really reasonable price and decided to get. Installation is very easy, but figuring out the dimmer took some time.
QUICK VERSION INSTALL NOTES: Remove driver side lower panel. Using nylon pry tool remove aluminum plastic trim piece from under vent. Remove single phillips head screw. Pull the external vent out and up from the bottom. Feed the P3 OBD2 connector end of the harness to the right of the dash vent tube (air supply tube that runs back into dash) and down. Run to OBD2 port and connect. I wrapped the rectangle shaped module up with something that would keep it from moving freely (left over heat shield from previous post). There is plenty of room on the right side of the dash vent tube for the module and harness. I used a 0.75" sq zip tie mount on the left side of the exterior vent...in order for the flap in the vent to work easily, you want the ribbon (flat) cable coming out of the vent (from the gauge) to be up against the inside vent wall and not interfere with the vent flap as it moves (controlled by wheel on outside of vent). I positioned the ribbon cable flat against the vent inside wall, did a U to the vent outside wall, and ran it down that left side (of the external vent) to the zip tie mount and tied it. Don't crush the ribbon cable with the zip tie. After the zip tie mount, bend the ribbon cable so that it runs under the external vent toward the right side. Upon assembly of the external vent, make sure none of the cables are impeding the vent from plugging into the dash vent tube. With the ribbon cable tied off, it should not be an issue, except a bit more force than normal to insert. Assembly of the remainder is reverse of disassembly. NOTES: Take care to make sure the external vent clips are properly attached prior to re-assembly. Also, before inserting phillips head screw, take a flashlight and shine in the hole to make sure the ribbon cable is not caught behind the screw hole so you don't drill into the ribbon cable upon installation.
IF YOU WANT THE DIMMER FUNCTION...
The P3 gauge display is pretty bright, at least for me (subjective). For the P3 Gauge to dim, you need to plug the green wire that comes with the P3 harness into an OEM wire that, when the light switch is turned on, runs 5V. Then code the gauge per mfg instructions. This was a headache, I mention the following dead ends so you can avoid. Scouring schematics on newtis I first measured voltage running to the unused (b/c I now have an android monitor) OEM Nav Display harness, it has a dimming wire. With vehicle on, this wire is always ON at 4V with light switch on and off. I then found that the Car Information Computer (Radio) has a dimmer. The big square OEM connector on the back is X13812 (search that on newtis for details). There are 40 pins and pin14 is the dimmer (
https://www.newtis.info/tisv2/a/en/e...cic/1VnXZ2ezKX). According to the schematic, the wire color is red/grey, however mine was a solid brown (more orange than the ground wire 'brown') (
https://www.newtis.info/tisv2/a/en/e...r-cic/H2MeJql6). Unfortunately, with the engine on (0V) and the lights are turned on it only carries 4V.
SO, I went back to the light switch.
[NOTE, you probably want to do this with the external vent uninstalled, not necessary, but makes it easier to tuck excess green P3 dimmer wire after this part.] I started here, but because of the connector type, I couldn't easily measure voltages with my voltmeter. The light switch connector is X10164 and has 12 pins (
https://www.newtis.info/tisv2/a/en/e...h-unit/cLvFXx2). The way this works, as I understand, the footwell module effectively sends the dimmer switch 5V, we adjust the dimmer switch, and the output voltage based on the switch position is sent back to the footwell module and on to all the other lighting controlled by the dimmer (
https://www.newtis.info/tisv2/a/en/e...8-x908/oqbIjlR). In the diagram below the dimmer switch has two wires, so which is variable and which constant? After trial and error, the Grey/Black Pin8 wire is a variable load (up to 5V) whose voltage is dependent on the dimmer switch (wheel setting).
The Green Pin5 wire is a constant 5V. I conceded further investigation because the display is pretty bright, and having the dimmer constantly on wouldn't be a bad thing. I used a T-Tap (20-22awg) into the oem green wire coming from pin5 and connected the matching spade connector that came with the P3 Gauge harness. The OEM cable in this lighting connector appears to be 20ga. I tucked the excess of P3 green wire in the available harness channel behind the light switch. Per the P3 instructions I coded the gauge to use the dimmer. DONE.
Please let us know if you find a better wire to use. TIA
Last picture not completely assembled...vent trim piece still out and wires beneath not tucked yet. ALSO, the digital display is more orange than in the pic below.
Attachment 2349642
External vent shown pulled out and rotated 180deg towards camera:
Attachment 2350158
Attachment 2349644