The old (Japanese) screen unit in my JDM car was a Kenwood FGZ204F2 system with 4 ports/ harnesses into the back. As part of a plan to replace it with a home brew build, this post is just the outcome my working out what the various pins do.
Car interface and audio bus ports
Car Interface 16-pin Port (#1)
Pin | Function | Notes |
---|---|---|
1 | +B | Always on 12V |
2 | GND | |
3 | ACC | Typically Automotive (ACC)essory, the second stop on ignition key. Sends power to the old unit. |
4 | GND | |
5 | CAN-H | CAN H & L are data protocol. |
6 | CAN-L | CAN H & L are also pins on the OBD2 port so guess data coming in here is the same |
7 | IGN | Ignition. Maybe another stop on ignition key? |
8 | PARKING | Goes position when handbrake on. Typically pulled to GND |
9 | REVERSE | Goes poitive when car in reverse...for reversing cam |
10 | SPD | If this is speed, weird that its been given own pin, isolated the CAN data |
11 | ILL(PWM) | Illumination/light? PWM is normally 'pulse width modulation'. Not sure |
12 | ILL(SMALL) | Goes positive when head lights are on (for back lighting of unit) |
13 | NC | Not used |
14 | NC | Not used |
15 | PTT | No idea |
16 | GND |
The interesting here is the CAN H and L pins. Must be the same data that is going through the OBD2 port, and how the old unit got speed, trip data etc.
I hoped there would be a pin for the external ambient air temperature since that was displayed on the old screen. There is not, so it must come through CAN.
Audio Bus 20-pin Port (#2)
Pin | Function | Notes |
---|---|---|
1 | ||
2 | ||
3 | ||
4 | ||
5 | ||
6 | ||
7 | ||
8 | ||
9 | ||
10 | ||
11 | ||
12 | ||
13 | ||
14 | ||
15 | ||
16 | ||
17 | ||
18 | ||
19 | ||
20 |
Camera and Navigation Unit
Navigation Unit 13-pin Circular Port (#3)
Going to delete this – think it fed to GPS and some Japanese centric traffic stuff.
Rear Camera 4-pin Port (#4)
An analog video signal. Going to delete this and replace with USB video