Technical factory head unit pin voltages

[arekp]

wonder if anyone knows which pin has the reverse camera trigger input, or is it through canbus?

it must be through pins 1-20, but the voltages I get are the same in neutral and in reverse:
pin 1: empty/blank
pin 2: 3.2V
pin 3: empty/blank
pin 4: empty/blank
pin 5: 2.6V
pin 6: 0V
pin 7: 0V
pin 8: empty/blank
pin 9: empty/blank
pin 10: empty/blank
pin 11: empty/blank
pin 12: empty/blank
pin 13: 0V
pin 14: 0V
pin 15: 0V
pin 16: 2.4V
pin 17: empty/blank
pin 18: empty/blank
pin 19: 1.9V
pin 20: empty/blank

for ground, I've tried pins 33 (reverse camera ground) and 43 (main ground on harness) , but outcome is the same

 

[s130]

The rear view camera (RVC) communicates with the BCM via LIN2

There are 4 LIN coms link on the Body Computer.

https://en.wikipedia.org/wiki/Local_Interconnect_Network

LIN (Local Interconnect Network) is a serial network protocol used for communication between components in vehicles. It is a single wire, serial network protocol that supports communications up to 19.2 Kbit/s at a bus length of 40 meters. The need for a cheap serial network arose as the technologies and the facilities implemented in the car grew, while the CAN bus was too expensive to implement for every component in the car. European car manufacturers started using different serial communication technologies, which led to compatibility problems.

Pinouts for the 5" and 6.5" Head Units

Sorry about the ordering but you can copy and paste then re-order if you want for clarity.

PIN Function
1 Can C1 H
28 N.C.
2 BH CAN H
29 Microphone 1 -
3 N.C.
30 Microphone 1 +
4 N.C.
31 Rear camera signal +
5 BH CAN H
32 Rear camera signal -
6 Audio_1 / Aux_In_right
33 Rear camera signal shielding
7 Audio_1 / Aux_In_ detection
34 N.C.
8 Audio_2 / RSE CD right
35 N.C.
9 Audio_2 / RSE CD detection
36 N.C.
10 Audio_2 / RSE CD left
37 N.C.
11 Can C1 L
38 N.C.
12 BH CAN L
39 N.C.
13 Backlighting for Media Hub
40 N.C.
14 N.C.
41 N.C.
15 BH CAN L
42 N.C.
16 Audio_1 / Aux_In_left
43 Earth
17 Audio_1 / Aux_In_Detection
44 +30
18 Audio_1 / Aux_In_Shielding
45 Rear right +
19 Audio_2 / RSE CD Shielding
46 Front right -
20 N.C.
47 Front left +
21 N.C.
48 Rear left +
22 N.C.
49 Rear right -
23 N.C.
50 Front right +
24 N.C.
51 Front left -
25 N.C.
52 Rear left -

 

[arekp]

thanks @s130, with multimeter I confirmed:
pin 31 was signal +
pin 32 was return -
pin 33 was shield

there is no individual line as the reverse trigger (like older cars have) but instead it all happens via the can bus

I added a cable to my after market head unit connector which was missing inputs at pins 31 & 32, adjusted some settings, and voila!

I've done a DIY guide on how to install an android head unit and retain the factory reverse camera input

And yes, the lines adjust as you turn steering wheel

 

[s130]

So you are saying that you have the CAN BUS trigger and control all working OK now?

Good for you. The info I posted re: LIN (Local Interface Network) data back to 2015 ish so no doubt Fiat have updated the technical info for later models.

 

[arekp]

yes, can bus trigger & control working for reverse, phone, volume, track, cruise control

 

[Boxer250]

Sorry for the thread ressurection, but I have done a bit of trawling and cant seem to find what Im looking for, hoping I can glean some info from this post.

I have a 2021 boxer with a VP2 radio fitted, the pinout sticker on the top matches exactly what I have seen at the top of this thread. Im wanting to add a 3.5mm aux port into the unit. (my old 2014 had one)

I have the 3.5mm/usb media hub and am now confused by the wiring. the 3.5mm side of the hub has green, white, red, black and white wires in a shielded lead, with a seperate yellow/black. Im presuming it needs some form of power, as even with USB connected (via PC) I have measured no output from any combination of the shielded leads with a decent auidio signal going in.

Can anyone let me know what the colour codes are please?

Alternatively, what does Pin 17 require in order to activate the AUX in? I'll just hard wire a 3.5mm lead into the back if I can learn how to trigger it.

Thanks in advance

Boxer

The rear view camera (RVC) communicates with the BCM via LIN2

There are 4 LIN coms link on the Body Computer.

https://en.wikipedia.org/wiki/Local_Interconnect_Network

LIN (Local Interconnect Network) is a serial network protocol used for communication between components in vehicles. It is a single wire, serial network protocol that supports communications up to 19.2 Kbit/s at a bus length of 40 meters. The need for a cheap serial network arose as the technologies and the facilities implemented in the car grew, while the CAN bus was too expensive to implement for every component in the car. European car manufacturers started using different serial communication technologies, which led to compatibility problems.

Pinouts for the 5" and 6.5" Head Units

Sorry about the ordering but you can copy and paste then re-order if you want for clarity.

PIN Function
1 Can C1 H
28 N.C.
2 BH CAN H
29 Microphone 1 -
3 N.C.
30 Microphone 1 +
4 N.C.
31 Rear camera signal +
5 BH CAN H
32 Rear camera signal -
6 Audio_1 / Aux_In_right
33 Rear camera signal shielding
7 Audio_1 / Aux_In_ detection
34 N.C.
8 Audio_2 / RSE CD right
35 N.C.
9 Audio_2 / RSE CD detection
36 N.C.
10 Audio_2 / RSE CD left
37 N.C.
11 Can C1 L
38 N.C.
12 BH CAN L
39 N.C.
13 Backlighting for Media Hub
40 N.C.
14 N.C.
41 N.C.
15 BH CAN L
42 N.C.
16 Audio_1 / Aux_In_left
43 Earth
17 Audio_1 / Aux_In_Detection
44 +30
18 Audio_1 / Aux_In_Shielding
45 Rear right +
19 Audio_2 / RSE CD Shielding
46 Front right -
20 N.C.
47 Front left +
21 N.C.
48 Rear left +
22 N.C.
49 Rear right -
23 N.C.
50 Front right +
24 N.C.
51 Front left -
25 N.C.
52 Rear left -

 

[Boxer250]

I have made some progress, but still cant get aux in to trigger.

From the back of the media hub:

White- 3.5mm tip
Green - 3.5mm ring
Black - 3.5mm sleeve
Yellow - illuminates media hub LEDs when connected to pin 13 of the VP2

I have connected the green/white/black to the respective pins labelled on the vp2.

That leaves red and another black.

Pin 17 on the VP2 (labelled DET in) measures at approx 3.2v. If I connect it to the red wire it drops to 1.6v. If I then plug in a 3.5mm jack it rises back to 3.2v. (still no AUX selectable as a source)

I feel like I'm 90% there, but no idea where the remaining black goes.