The easy way to go on these vans is the iDatalink module with the ADS AL(DL) CH4 firmware.  Does it all for you.  Lock, UnLock, Arm, DisArm, Sliding Doors, Bypass, Parking lights, Tach, Brake, Door & Trunk status.  Their guide gives you all the wire colors & location.  I did a 2009 Caravan ( which should be the same as 2010's ) , very straight forward.  Plenty of room under the dash. 

Here is the iDatalink Web site:   http://www.idatalink.com/helpdesk/

Audiovox info for 2010 VW Routan

Audio/Mobile Video        
 WIRE  COLOR  POLARITY  LOCATION 
 Battery  YELLOW/RED  (+)  RADIO HARNESS 
 Ground  BLACK/WHITE  (-)  RADIO HARNESS 
 LF Speaker (+)  GRAY/VIOLET 
   THESE WIRES ALSO GO TO THE FRONT LEFT TWEETER 
 LF Speaker (-)  GRAY/YELLOW 
 RF Speaker (+)  DARK GREEN/VIOLET 
   THESE WIRES ALSO GO TO THE FRONT RIGHT TWEETER 
 RF Speaker (-)  DARK GREEN/YELLOW 
 LR Speaker (+)  DARK GREEN/TAN 
 LR Speaker (-)  DARK GREEN/GRAY 
 RR Speaker (+)  DARK GREEN/BROWN 
 RR Speaker (-)  YELLOW/GRAY 
 Amp Location  SEE AMPLIFIED AUDIO TIRM FOR AMPLIFIER INFORMATION 
 Steering Cntrls  YES 
 Speed Cntrl  NO 
 Radio Security  YES 

 Security        
 WIRE  COLOR  POLARITY  LOCATION 
 Battery  LIGHT BLUE/RED  (+)  IGNITION SWITCH HARNESS 
   THIS WIRE ONLY SUPPLYS 10 AMPS OF CURRENT, FOR HIGH CURRENT APPLICATION GO DIRECTLY TO THE BATTERY 
 Ignition 1  PINK/WHITE  (+)  WIRELESS IGNITION MODULE IN STEERING COLUMN 
 Starter 1   
   THIS VEHICLE USES THE CAN DATA NETWORK FROM THE WIRELESS IGNITION MODULE IN THE STEERING COLUMN
FOR REMOTE START FUNCTIONS. USE AN APPROPRIATE ADAPTOR FROM A SECURITY MANUFACTURER FOR REMOTE START 
 LF Latch  VIOLET  (-)  AT TIPM MODULE ON DRIVERS SIDE OF ENGINE 
 RF Latch  VIOLET/WHITE  (-)  AT TIPM MODULE ON DRIVERS SIDE OF ENGINE 
 LR Latch  VIOLET/GRAY  (-)  AT TIPM MODULE ON DRIVERS SIDE OF ENGINE 
 RR Latch  VIOLET/YELLOW  (-)  AT TIPM MODULE ON DRIVERS SIDE OF ENGINE 
 Trunk Trigger  VIOLET  (-)  AT TIPM MODULE ON DRIVERS SIDE OF ENGINE 
 Parking Lights  WHITE/BROWN (L) & WHITE/ORANGE (R)  (+)  AT TIPM MODULE ON DRIVERS SIDE OF ENGINE
 
 Convenience        
 WIRE  COLOR  POLARITY  LOCATION 
 Parking Brake  DARK GREEN/WHITE  (-)  AT VEHICLE PARKING BRAKE SWITCH 
   ALSO IN HARNESS TO GAUGES 

 Remote Start        
 WIRE  COLOR  POLARITY  LOCATION 
 Battery  LIGHT BLUE/RED  (+)  IGNITION SWITCH HARNESS 
   THIS WIRE ONLY SUPPLYS 10 AMPS OF CURRENT, FOR HIGH CURRENT APPLICATION GO DIRECTLY TO THE BATTERY 
 Ignition 1  PINK/WHITE  (+)  WIRELESS IGNITION MODULE IN STEERING COLUMN 
 Starter 1   
   THIS VEHICLE USES THE CAN DATA NETWORK FROM THE WIRELESS IGNITION MODULE IN THE
STEERING COLUMN FOR REMOTE START FUNCTIONS. USE AN APPROPRIATE ADAPTOR FROM A SECURITY
MANUFACTURER FOR REMOTE START 
 Anti-Theft Type  DAIMLER SENTRY KEY® VEHICLE IMMOBILIZER 
 Anti-Theft Descript  THE KEY SENDS AN RF SIGNAL TO THE BCM MODULE THROUGH AN ANTENNA
LOCATED AROUND THE IGNITION CYLINDER 
 Speed Sense  DARK GREEN/BROWN  (AC)  POWERTRAIN CONTROL MODULE 
 Parking Lights  WHITE/BROWN (L) & WHITE/ORANGE (R)  (+)  AT TIPM MODULE ON DRIVERS SIDE OF ENGINE 
 Brake Lights  WHITE/DARK GREEN  (+)  AT SWITCH ABOVE BRAKE PEDAL 
 Reverse Lights  WHITE/LIGHT GREEN  (+)  AT TIPM UNDER HOOD 
 Horn  DARK GREEN/VIOLET  (-)  IN HARNESS AT STEERING COLUMN 
   ALSO IN HARNESS TO GAUGES 
 Rear Defrost  DARK BLUE/WHITE 

 Modules        
 WIRE  LOCATION     
 Module 1  TIPM - UNDER HOOD ON DRIVER SIDE OF ENGINE COMPARTMENT 
 Module 2  PCM - ON DRIVER SIDE FENDER AREA UNDER HOOD 

 Doorlocks/Windows        
 WIRE  COLOR  POLARITY  LOCATION 
 Power Unlock  VIOLET/DARK GREEN  (-)  IN HARNESS TO DRIVER DOOR IN DRIVER KICKPANEL 
   UNLOCK IS (-) THROUGH A 100 OHM RESISTOR, SAME WIRE FOR LOCK, MUST USE RELAYS 
 PowerLock  VIOLET/DARK GREEN  (-)  IN HARNESS TO DRIVER DOOR IN DRIVER KICKPANEL 
   LOCK IS (-) THROUGH A 330 OHM RESISTOR, SAME WIRE FOR UNLOCK, MUST USE RELAYS 
 LF Window Up  ORANGE/LIGHT GREEN  (REV)  AT DRIVER WINDOW CONTROL SWITCH 
 LF Window Dn  ORANGE/WHITE  (REV)  AT DRIVER WINDOW CONTROL SWITCH 
 RF Window Up  ORANGE/TAN  (REV)  IN HARNESS IN DRIVER KICKPANEL TO DOOR 
 RF Window Dn  ORANGE/GRAY  (REV)  IN HARNESS IN DRIVER KICKPANEL TO DOOR 
 LR Window Up  ORANGE/WHITE  (REV)  IN HARNESS IN DRIVER KICKPANEL TO DOOR 
 LR Window Dn  ORANGE/GRAY  (REV)  IN HARNESS IN DRIVER KICKPANEL TO DOOR 
 RR Window Up  ORANGE/LIGHT BLUE  (REV)  IN HARNESS IN DRIVER KICKPANEL TO DOOR 
 RR Window Dn  ORANGE/DARK BLUE  (REV)  IN HARNESS IN DRIVER KICKPANEL TO DOOR 
 
     
  Note: Audiovox makes no representation or warranty with respect to the above information including
its accuracy, completeness, or its freedom from third parties' proprietary rights. Audiovox disclaims
all liability or responsibility for errors or omissions therein or any decision made by the recipient
in reliance thereon. The installer must verify any circuitry with the proper test equipment prior to
installation.  

Howie, thats why I like the iDatalink module.  It provides a (-) Door and Trunk status signals for you from the vans CanBus.  I haven't done an alarm on one of these yet but you are probably correct.  If you get a false alarm trigger, do the Type B diode isolation from Direct Fax 1076.

http://www.the12volt.com/installbay/uploads/Tech_Tips_1076_Door_Trigger_Isolation.pdf

how to chak car canbus wire please help