Locking doors from the back of the van. ~ Stop me before I do something silly

[Willoughby]

Hi All

Soooo. I have a long weekend and plan to do some bits and bobs on the van to make it more of a camper. One of them is to have a go at adding a secondary central locking lock/unlock buttons for the back of the van.

Plan is to tap in to the switch on the driver door and run a switch in parallel from it. (Prob from the BCM side rather than the switch) Is this a bad idea, will hindsight catch up with me next week.?

Thoughts

Kev

 

[Pauly]

It's not that simple the lock unlock button works on resistance not just straight switching
If you run the cables I would oversize them to help keep the resistance of the cable low and think you would need to use a genuine door switch or figure out the resistance and replicate it with resistors
Send me a PM tonight and I will dig out more details for you or better still send me your number and I will call you tonight when I have had a look and explain it better

 

[mhill]

I feel your pain, something I've wanted to do.

 

[Willoughby]

genuine door switch

Cheers Paul

I will PM my number. I figured I may have to mock up a circuit board to replicate the switch. Would be great if you have access to the values required, failing that I will get an original switch.

@ mhill ~ I will post up let you know how I get on.

Kev

 

[Willoughby]

Think it best to start with video and work backward

C9S

• Willoughby
• 28 Aug 2017

This is where the disclaimer goes. This is what I did, no idea if safe or allowed so best to check before you even think about trying it out.

I took the lock/unlock switch apart to find out how it worked.



Basics are when unlock is pressed it connects the yellow wire to earth. When lock is pressed it connects the yellow to earth via a 7686Ω resistor.

Next step was to piggy back the existing yellow wire direct from the BCM. I took this new wire from the BCM and an Earth to a breadboard. Then attached two switches and to get the resistance spot on I used a 501 potentiometer and 1K resistor in parallel. (As the resistor on the switch board was an 86A with a 1% tolerance.)





When I hit the buttons and the switches worked a treat.

As a test, I played about with the resistance values switch fails about +- 10 % 850 690.

Good news is there is no need to faff about the resistor VW use is a standard one. I have ordered 5 from Ebay £2.36 delivered, will post up a pic and circuit drawing when they arrive.

Kev

 

[Pauly]

Awesome work there and knowing there is a 10% tolerance should make it a bit easier to replicate

 

[andys]

Nice work, one of those threads that I bookmark for future reference

 

[DaveyB]

Frickin awesome, only you lost me at 786 ohm resistor! Can see you may be tasked to make up kits and some "Janet and John" instructions, for us thicko's.

 

[Willoughby]

Frickin awesome, only you lost me at 786 ohm resistor! Can see you may be tasked to make up kits and some "Janet and John" instructions, for us thicko's.

Well.... I have ordered all the bits to make a module that will plug in and give u a remote control for the back of the van. Saves running wires and cutting in to van wiring. Parts currently on slow boat from china soon as they arrive I will get instructions sorted.

Kev

 

[Loz]

Well.... I have ordered all the bits to make a module that will plug in and give u a remote control for the back of the van. Saves running wires and cutting in to van wiring. Parts currently on slow boat from china soon as they arrive I will get instructions sorted.

Kev

ace! put me down for a kit please ...

 

[Willoughby]

Going away wild camping soon and decided to add a lock switch until the remote parts turn up.

 

[mhill]

Would also be nice to add a lock button on the passenger side like the drivers. @Pauly is there a OEM part for the passengers side with door locking?

 

[Pauly]

LHD would have this so would think so

 

[mhill]

LHD would have this so would think so

I thought of that but it would also have two electric windows switches.

 

[Vinci]

Going away wild camping soon and decided to add a lock switch until the remote parts turn up.

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Bl**dy clever stuff. Respect. Don't understand it, mind.

 

[DaveyB]

Watching with considerable interest. Need to do something like this in mine, since you can't operate the inner rear switch when lying on the kombi bed unless you have a noodle for a finger.

 

[Pauly]

I have some resistors now what style of switch do you want ?
Can have rocker or toggle but may depend on where you want to fit it ?

 

[travelvolts]

I think you have stated that incorrectly, the resistor is on the unlock line, not the lock. Also, be aware that in the event of a theft you may have problems with the insurance as this method is not "safe" if the extra switch is not hidden well.

 

[Loz]

I think this circuit is disabled when locked with the remote.

 

[travelvolts]

It didn't used to be on the T5 so worth checking.