We've gotten a bit spooked by the spate of RV break-ins that have been reported recently, so we decided to install an alarm system.
As reported here:
I've chosen the Viper 5706V alarm, which provides 2-way communication to its key fob with (allegedly) up to 1-mile range, which should be good at and around campsites and when parked at restaurants, etc. It also can be armed/disarmed with the buttons on the Sprinter OEM keyfob. I also purchased a DBALL2 "bypass" device to interface with the Sprinter's CANBUS. This eliminates all the wiring to door sensors, door lock solenoids, etc. Instead, the DBALL uses the CANBUS to detect lock/unlock, door open/close and ignition events, and also to do things like actuate the door locks, flash lights, and so on. The whole thing involves only four wire connections to the van: +12, GND, CAN+ and CAN-. The installation is really quite trivial. Figuring out exactly how to do it, not so much. So, I thought I would document the things that initially confused me, to make things easier for others who might want to do this. These comments will obviously be specifically with reference to my 2014 Sprinter and the 5706V, but many other systems are very similar. A company called Directed dominates the market, and most alarm brands you see are made by them and thus are very similar. Also note that the DBALL2 appears to be the ONLY Directed device that supports 2014+ Sprinters (there are many others for older model years.) I suspect they have standardized on this platform.
OK, here's what you need to know:
--First of all, a few words about CANBUS
(a) This list is filled with ominous warnings about how fragile the Sprinter's CANBUS is and how you should never even think about messing with it. This is mostly nonsense. Although it is true that virtually every system on the vehicle can be impacted by CANBUS problems, it is also true that the CANBUS is an open standard specifically intended to support interoperability among independent devices. If you don't trust yourself to make clean, professional connections, then find somebody whom you do trust. But, a properly-installed addition to your CANBUS is perfectly OK.
(b) Almost all instructions you will find on the Net for installing an alarm talk about tapping into an existing CAN connection (e.g., the radio) and soldering in your wires. IGNORE THESE INSTRUCTIONS. The sprinter has a very simple and convenient provision for plugging in additional CANBUS devices without disturbing any wiring. This is the only approach you should consider. To access the CANBUS hub, simply remove this plastic panel directly below the headlight switch (one screw):
Behind this panel, on the right, you will find a vertically-mounted connector with half a dozen little plugs in it, and space for more. It is hard to see because the connectors are facing away from you. In the center of the strip, you will see a little slot with a plastic tab that holds the connector to its bracket. Press the tab with a small screwdriver and slide the connector upward, and it will pop out so you can see and access the plugs and sockets:
Those little plugs are simply 2-pin "header" connectors that are commonly used for internal connections to PC boards in computers, etc. I THINK that they are 3mm, but I'm not sure. I found one that fit in my junk box. I'm sure they are available from DigiKey. Mine looks like this:
You can see my connecter plugged into the bottommost position on the bus.
As I said, this is a little box whose job is to translate between CANBUS and alarm-talk. It can do this in two different ways, as shown here:
For old-school installations, it breaks out a whole bunch of signals (both input and output) like "door status" or "turn on parking lights". This is called "W2W" (wire to wire) mode. The other mode is "D2D" (digital to digital), which uses a serial communications port to communicate with a compatible alarm system, which means you can ignore most of the wires. We are using D2D.
The DBALL2 hardware is generic, and can be used with most any brand of car. HOWEVER, it needs to be programmed for a specific vehicle. There is very specific firmware for current-production Sprinters--no other will work. Although it is possible to buy an inexpensive programmer and do this yourself, it is easy to find vendors who will ship the DBALL pre-programmed for a vehicle that you specify. I did the latter. They do it for free.
There are only three connections you need to make to the DBALL: (1) A 4-wire D2D cable that goes between the alarm and the DBALL. This also provides power to the DBALL; (2) a 2-wire connection to the CANBUS. N.B.: you MUST get the polarity of these wires correct. The orange/brown wire from the blue DBALL connector is CAN-LOW, and must be connected to the BROWN side of the hub. Orange/green is CAN-HIGH and goes to brown/red. Don't screw this up; (3) The final connection is the gray/black wire on the red connector. This confused me at first, so I will give it its own section.
The DBALL diagram shows the gray/black wire as going to "Ignition Output" of the the alarm, but doesn't explain what this means. The 5706V supports remote starting of many vehicles, but this feature is not available on the Sprinter. To support this feature, the device has a huge, high-current 10-pin connector. We don't need any of these connections except the one with the pink wire, which is where the gray/black wire goes. You could use the huge wire harness that comes with the alarm, but I just crimped a spade connector onto the gray/black wire and plugged it into the appropriate lug:
And, that's it for the DBALL.
The alarm is pretty simple as well. In addition to the gray/black wire and the D2D cable, you need Continuous power (red), Ground (black), and Siren out (brown). The latter goes the the red wire from the siren. The black wire from the siren goes to ground. There is also a fob-like thingie with a button and an LED. This is meant to be mounted at the top center of your windshield. Its main function is as the antenna for communication with the keyfobs. The button controls things like "valet mode". Finally, the LED flashes when the alarm is armed, scaring away ruffians. The final connection is a 4-wire cable that goes from the alarm to the shock sensor. This confused me too:
The shock sensor cable plugs into one of two 4-wire sockets on the side of the alarm. I don't think it matters which one you use, but I'm not sure. The thing that confused me is that the 4-wire cable isn't symmetrical, even though it has the same connector on both sides. The difference is a little wire loop that shorts together two pins on one side, and an unconnected green wire on the other. I think these have to do with multiplexing multiple sensors on the same line. We don't need this. The question is, which side do you put the loop. The answer is that it goes on the sensor side (and thus the green wire goes on the alarm side).
So, that's it. As you can see, there are actually only four wires that touch the Sprinter in any way: Power, GND, and the two CANBUS wires, and none of these require stripping or soldering any existing wire.
Initializing the DBALL:
The last step involves initializing the DBALL2. To do this, you connect up all the wires EXCEPT the D2D cable from the alarm. To initialize the device, you hold down the button on the DBALL while you plug in the D2D cable. The LED on the DBALL should light up orange, at which point you release the button. Then you turn on the ignition with the key. If the device successfully synchs with the CANBUS, the light will turn green, and the device will reset. That's it--you are done. There are instructions for synching the keyfobs, but mine just worked.
Sorry for the long post, but I hope it will dispel some of the fog that the alarm companies intentionally spread around this whole topic.