In case anyone tried to replicate this I'll add the note that I used TWO layers of the dual-lock fasteners in order to get the mounting plate to sit out more proudly. I was calling myself a hack when doing it but in the end it seems to do what was needed. Keep in mind that the more you bring the bottom out the less grip the mounting plate's lip will have in the CD slot: you'd need to alter the bend/angle to gain back the binding.

I'll also note mounting plate can be rotated a bit left and right as the HU is convex which means that the plate can roll around that convex a little. Not sure if this is a feature or the result of a marginal design!

 

Diesel, this is an awesome idea to bypass all the headache of the MOST system and the wiring that comes with a full aftermarket HU install. Awesome write up. I’ll be sure to link people to this when they post asking about HU installs with the HK speakers

 

Thought I'd provide some more info.

I know of someone who followed my installation but instead of messing with the custom mount just used the suction cup bracket provided with the DVR and stuck it on the car's display. The suction cup mount that I had would work like for this other unit. Looking back I think I might have been able to skip the metal bracket and just go direct with the dual-lock fasteners: one day I might check it just for giggles.

 

This is a heckuvan idea, DieselBound, and thanks for documenting it as well as you did.

I have done an Android head-unit upgrade in W220's (same technology era, similar speaker layout). For us, the Android update was a good idea; the wife really wanted a dash-cam after some jerkosaurus had hit her previous car and then sued her! She eventually won the case, but she learned her lesson. Plus, she wanted a factory appearance. The sound system with the Android head unit is as good as the factory system that it replaced. It did take some significant work, though.

But not everyone needs this. Those of us on a budget--and E320 CDI's are remarkably budget-friendly cars, as I've found--can get updated features, as you have, even more easily. You also get rather a bit more screen real-estate with your solution. And, given how good the factory W211 sound system is, you retain all that goodness, too.

Nice work here, man.

 

I like this! I'm looking at the Atoto P8 as a candidate, which includes a backup camera as well as the dashcam. A bit more pricy at $259 on Amazon, but includes Android Auto Play and Apple car Play.

 

Max, I went through AliExpress: MUCH cheaper. Everything's coming from China anyway. Only issue is support. If something is sold through a US vendor (like Carpuride) then there's likely some support. Note my experience with installing a backup camera. I suspect that most of these types of units can only use bundled cameras (cheap). Again I plea for any help from video folks on how I can get my backup camera working with my unit. These cars really do need backup cameras: mirrors are really weak (small).

Will note that the offerings are now tending to come with added, bulky forward-facing cameras and that this can make mounting such as I went with a bit more difficult.

Here's another view of my install that I think gives a better perspective on how it looks:

20230625_090725.jpg

• DieselBound
• Jun 30, 2023
• 3

Shot of "completed" interior, front cabin area. Installed newer style HVAC control. Installed...

 

Thanks for the inspiration! I was happy with my Bluetooth to aux solution but I want rear camera. Not keen on a huge screen though. I tried a 5” screen but it had a dash cam which made it bulky to mount where I wanted it. I have a dash cam anyway.

Here’s a 7” screen:

It hangs on a magnetic phone mount on the CD slot:

It doesn’t use the magnet. The screen ball mount goes right to the CD slot holder:

Yeah, a bit wobbly but tolerable.

What’s really annoying is exposed wires:

From top: audio, rear camera, USB power. I’m waiting for a USB cable with a right angle end which should stay out of the way of putting the key in the slot. The conduit will tuck into the underdash panel. I’ll somehow attach the cable to the side of the console. And vacuum around the pedals.

Sixto
05 E320 wagon 206K miles

 

This is what I ended up doing.
I installed a Bluetooth receiver to the back of my COMAND deck in my 2008 ML just so I could play music and receive calls over the speakers but I added a 9.26" screen similar to above and that allows Bluetooth music streaming via the Bluetooth receiver I installed from my phone.
Sucks having an additional screen and wires to tuck away but after not getting audio from my Android deck this is the next best route.

 

I'll note that the DVR unit I got uses ONE cable to carry USB, AUX and power*. There's another jack/cable for a reverse camera but I'm still looking into getting that working (for my camera) and I modified the front cover of my console ashtray door to sneak in wires/cables from the upper left corner and with the main cable having a 90 bend in it it all tucks/routes very nicely. Refer to my thread for more information.

* This may have changed for "advanced" units (they still sell the same unit I have, it's now only $68 USD). Having a readily accessible USB port could be useful. On my unit I fished a USB cable from/through the ashtray area and under the shifter and into the center armrest console and I plug my phone in there (if I ever am bored I'll create a docking station- I created a custom docking station in my VW Golf which was awesome but it was customized to the phone and when I replaced the phone things wouldn't like up and connect properly).

 

FINALLY got a workable solution for a backup camera!

Key points for success:

1) Match camera's video format/display to the DVR unit's: got the seller of my DVR unit to give me specs but they turned out to be WRONG! (they said 720p when in fact it was 1080p);
2) Identify pin connections on 2.5mm jack as pertains to the unit's requirements- I had to mess around (no help from anyone) and found that using pins 2&3* for video and pin 4 for ground works.

* I don't know if both 2 and 3 are needed but the RCA->2.5mm jack adapter I got had video on both and that works: if it works then don't mess with it! 2 and 3 are fairly common video pins; 4 is also fairly common for ground; using these are references for a starting point should get one there fairly quickly. NOTE: the DVR might be expecting to see something on the non-video 2 or 3 pin as a trigger signal to switch the display.

I still need to do the permanent install -need to tear the trunk apart and install this latest camera [1920x1080 AHD]- but I know all will be good now.


For reference here is the camera and adapter combination that ended up working for me:
Camera
https://www.amazon.com/gp/product/B0CGNL6XVT
Our AHD backup camera only supports AHD 1080P

Adapter
https://www.amazon.com/gp/product/B08QZ7W9CX
This 20cm RCA to AUX 2.5mm cable is for connecting to the video input jack on GPS Tablet such as Tomtom Garmin DVR Dashcam & RV Tablets. Plug and play, convert RCA to 2.5mm AV-IN easily.

 

Great news! That is a nice looking camera. Is there a natural location for it on the trunk lid?

 

Here's where I put the first one (and where the new one will go):

Issue is that the camera's post (threaded tube that the wires go through and a nut spins down to hold the camera in place) is pretty close to the trunk latch. I failed to account for the width of the NUT and ended up having to (using a soldering iron- total hack!) melt some of the latches' plastic (didn't affect it) in order to run the nut down. I'd have been better served to move the hole to the right about 1/4" (perhaps not even that much). It looks like the nut for the new camera isn't as bulky in which case I should be OK.

 

Here's a shot of what it looks like in that area of the trunk (after I drilled- I had to melt away some of the plastic in order to get the nut to wind down). Access into this area isn't very good. I was stuffing a hot soldering iron in there and not really being able to see (struggle to also bring the lid down and keep it down in order to reach).

When I open things up to install the new camera I think I should look at the electrical connection on that latch (appears to be a bit of corrosion there?)!

 

Does the latch unit have a blank plate for a camera like the wagon latch? It’s the right place for a camera but you have to open the plastic case to route wires. A lot of work to get to it in a wagon. Looks easier in a sedan.

Sixto
05 E320 wagon 207K miles

 

Sixto, not aware of any such. I know that there are cameras that are license plate combos; I avoid these because of ratings (lights tend to wash things out; also no adjustment* on them).

* Speaking of adjustments, the camera that I got allows for a ton of adjustment. The initial one had wedge-shaped shims that allowed you to alter the tilt.

 

What kind of voltage is typically required for a reverse signal?

After having what is my final installation of the backup camera I find that the DVR's display doesn't automatically switch when the car's shift selector is in reverse. I can manually bring up the camera fine in which case power to it is working: it gets power switched through a relay via trigger from the backup light circuit. Video means I've got video and ground working: video is on pin 2 and ground on pin 4.

I believe that it can only be due to either insufficient voltage on the reverse signal wire (most likely pin 3) to the DVR or the DVR is using a different pin from the jack for the reverse signal.

According to one DVR camera manufacturer, they're running four wires, they have 5v on pin 1 (tip), video on pin 2, reverse signal on pin 3 and ground on pin 4. I don't believe that I need that 5v on pin 1: my display shows the camera feed in which case I know I don't need it for that. Either my DVR is looking for a reverse signal on pin 1 OR it requires a higher voltage (on pin 3).

Is there a "reverse wire" off of the gear selector? 12v? If not then I'll just run a separate wire from the back (no big deal) and wire up my own cable end. I ordered some 2.5mm jacks with bare wires [four]. Will first test by feeding 12v to the #3 pin before committing to running a wire the full length of the car.

 

https://www.benzworld.org/threads/location-of-reverse-lights-switch.1489323/ talks about where the reverse signal module is. I don't know if it is some CAN-BUS signal that will be hard to tap into for the DVR. Anyway, I think easier to just run the wire from the reserve light. My backup camera signal to Android head unit works that way, getting 12v.

 

IIRC no dedicated reverse wire from the shifter, and I doubt it works on 12V anyway.

I don’t follow how you wired the reverse signal. My DVR has a 4 contact mini plug for reverse which covers trigger and video signal. Reverse trigger is from the tail light assembly which has an incandescent reverse bulb. I don’t know if it’s a 12V bulb. I tapped into it and it works. An LED might not get 12V from the SAM.

Our other cars have a reverse signal into the head unit separate from the RCA jack video input. The camera kit made it easy with a couple of wires sheathed in the video cable. The reverse light puts the head unit in reverse mode and provides power to the camera.

Sixto
05 E320 wagon 207K miles

 

jyl, yeah, was afraid that it wouldn't be easy (and that canbus is likely in the mix), that I'd be able to bring up instances of people doing such.

Sixto, the default DVR cameras for these units DO work out of the box: I have/had one- I hacked up the cable for early testing. I am NOT using one of those cameras (they'd look like total crap on this car). Acceptable, to me, cameras use RCA and I have to get the right (RCA->2.5mm jack) adapter to get the video to work. Problem is that after getting the video and ground pins figured out I am now seeing that I'm likely going to have to run a separate 12v wire to trigger the DVR. Because my current 2.5mm jack has pins 2 & 3 wired together* (video signal from the RCA side going out on both pins) I thought that that would be sufficient to provide the reverse signal (on pin 3); I've only got 1v showing up on pins 2 & 3 (as they are tied together they SHOULD be the same!) and that pin 3 tends to be what is used for the reverse signal I'm thinking that I need 12v on pin 3 and that can only happen via a new cable or to add a separate power wire (I'd be pulling from the output side of the relay I have that is operating off the reverse wire circuit at the tail light).

* I've run across various adapters that do all sort of weird pinouts. Rarely does anyone actually state what their pinouts are and getting any response is an exercise in futility: it's endemic!

At this point it is clear that I'm going to have to break down and do my own custom splicing. I have no idea what the pinout on this camera's 4-pin connector is. I've already run across this, the connectors tend to vary as how they connect up to the cameras, there's no guarantee that the end will fit. This is just the physical connection aspect, there's then the wire connection configurations -pinouts- and the odds are I'd have to hack that. I think I'm better off just keeping the existing RCA wire for the video, running a separate 12v line for the reverse signal and splicing everythhing into a 2.5mm jack pigtail end. Running a four pin connector wire is going to be more work than just running a single power wire.

Bottom line: I'm doing a "custom" install, out-of-box stuff won't plug and play for me. I just tend to get myself into these predicaments, owing mostly because I have my own idea of what I want (I'm non-conformist ).

 

Not sure if I shared already but this is the camera I have:

https://www.amazon.com/Spedal-Carplay-Universal-Waterproof-Rearview/dp/B0B887FD5Y/ref=asc_df_B0B887FD5Y/

It works out of the box. The case is big and the mount to tip is downwards looks home made. I’ll replace it with a smaller camera that has wires through the mounting screw yet has a 4-pin connector; no RCA. I hope it plugs into the 4-pin wiring I’ve already strung and works with the DVR. Sadly, it has about half the 1080p resolution. I haven’t found the camera style I like with 1080p resolution and RCA-less wiring.

Sixto
05 E320 wagon 207K miles

 

Sixto, if I hadn't already drilled a hole that goes into the bottom of the trunk's lip [sedan] I could see that camera as a good option.

 

I've been noodling with the idea of simply using an Android tablet as the display, but then I'd have to figure out things like the connection between my Android phone and the tablet to share data service, phone calls, contacts list. Would also need to figure out the reverse camera deal. Maybe there's an app for that? The tablet would have things like Maps, Waze, bluetooth, aux-out to plug into the car's audio system, music player or podcast app.

 

You can use your phone as a hotspot or tether the tablet to your phone (if those aren’t the same thing). Will the tablet connect to the phone whenever you start the car?

How does the tablet automatically turn on/off with the car?

There are Bluetooth cameras but how would you trigger the tablet to automatically display rear camera when you shift to reverse?

Sixto
05 E320 wagon 207K miles

 

Max, yeah, I'd encountered lots of folks doing that. Not much different. For me it was a matter of where to put the display. These portable DVR units (or whatever they're really called) are a bit more compact so easier to mount/place. Not sure about how one would get the display to switch for a reverse camera: given that an Android tablet is an infinitely more programmable/customizable device I don't see it really being a problem: just automatically switch when detecting video input. I'd think that you could install Android Auto on the tablet.

 

Making the reverse camera work with no driver input is the trick (for my purposes). I need that to be seamless and reliable. The DVR provides that capability up front, so that's the easy button.

I may research this a bit. There are fiber optic scope cameras that connect to a smart phone by USB, perhaps there is an app that can be used with a reverse camera that is triggered by the reverse lights and connects to the tablet USB port.

 

You’ll have to split the USB port’s function as power source and video source. Is that just a USB splitter?

Sixto
05 E320 wagon 207K miles