Opel/Vauxhall Zafira B/Astra H power fold mirrors via remote

25 Feb

Since I bought my Zafira in 2013, I dreamed of a modification, that would enable to automatically fold/unfold the mirrors via the remote key. Finally, after I tinkered with the driver door switch in December 2018, enabling folding/unfolding of the mirrors even without ignition voltage present in the switch, I decided to create a module that would enable me to fold the mirrors upon locking and unfold upon unlocking the car (like you get it with many other car brands as standard).

Upon reverse engineering the driver door switch I discovered that the mirrors are operated via a switching relay controlled by a micro controller. Upon pressing the button, the relay is engaged, sending voltage to mirror motors for a defined period of time. The Opel implementation is really simple and there is nothing fancy like detecting the position of the mirrors or stop switches. The controller just cycles through unfolding/folding upon each press of a button. The voltage is applied to the mirror motors for about 4 seconds and since the full folding/unfolding movement takes less than 2 seconds, the motors are designed to sustain applied voltage even when the mirror is already in end position without burning out or damaging the gears. The press of a button is registered only after the full fold/unfold cycle so you cannot reverse the movement during and short after the mirrors are folded/unfolded within this 4 seconds cycle.

To mimic this behavior I’ve decided to use similar approach with a module containing a micro-controller and relays. The controller would detect lock/unlock signals from door lock motor wires and control two relays – one would disconnect mirror motors from driver door switch unit connecting them to the module during the operation of folding/unfolding (and connect them back to driver door switch unit afterwards) and the second relay would function the same way as the relay in the driver door switch unit – fold and unfold the mirrors by sending 12V to mirror motors for a defined time period. Since I have a deadlock function on my Zafira, which can be engaged with the second press of lock button, I wanted to have an option to fold the mirrors either on standard lock or deadlock, preferably selectable by a switch on the module.

PFM module schematics
Initial sketch of PFM module

For the first relay I chose automotive relay from TE V23086-C2001. It’s a double relay with two coils which would be connected in parallel to the controller. When the module is not in use, the mirrors are  connected to door switch unit via pins 14-13 and 24-23 and after powering the coils, the mirrors would be connected to the module via pins 14-15 and 24-25. For the second relay I picked the identic relay to the one used in door switch unit – Panasonic ACTE3H2 – which would cycle/reverse +12V and GND to the mirror motors through two coils.

For the micro-controller I needed something that can accommodate four inputs:

  • First input detecting ignition voltage – the module would get disabled once the car is started to prevent folding of the mirrors during drive if someone pressed central door locking button on the dash or when engaging auto-lock feature (once the car drives over 10km/h).
  • Second input would detect unlock signal from the wire going to driver door lock motor.
  • Third input would detect lock signal (same as above).
  • And finally, fourth input would detect deadlock signal (again, same as above).

I could save one input by using just one input for lock/deadlock signal, but I would have to rewire this input to either lock or deadlock if I wanted to change the folding routine. As I wrote earlier, I wanted the be able to change it with a switch on the module.

For controlling the relays I needed three outputs on the controller:

  • One output for operating both coils on TE V23086-C2001 (connected in parallel).
  • Two outputs for operating coils on Panasonic ACTE3H2.

As I had a little experience with micro-controllers and assembly language, a friend of mine suggested using PICAXE micro-controller, which can be programmed via BASIC language. Upon inspecting various models, I picked PICAXE-14M2 model, which accommodates 12 programmable inputs/outputs – which game me enough inputs and outputs for the task.

The PICAXE controller runs on 5V so my module needed stabilized 5V supply to power the PICAXE chip as well as another circuitry to step down 12V inputs from the door lock motors to a voltage accepted by PICAXE and also to step up 5V outputs from PICAXE through transistors to drive the 12V coils in the before-mentioned relays. Luckily, the same friend provided to me all the schematics together with the list of components (he is a great guy with a lots of talent, go and check out his page dedicated to other modules for Opel/Vauxhall cars.

Once all of this was sorted out, I started assembling first experimental breadboard circuits to test the power supply, inputs, outputs, and PICAXE programming.

After having my first prototype ready, it was time to investigate the timing of lock/unlock signals on my car. I tapped the wires going to door lock and hooked up an oscilloscope to graph the voltage on the wire.

Here is a graph showing how is voltage applied to the wires during unlocking/locking/deadlocking process.

Unlock/Lock/Deadlock signals

Then it was time to program the PICAXE micro-controller with correct timings and combination of input signals. Once all of this was done and ready, I finally hooked up the prototype to the car and did my first couple of tests. I must say it felt really satisfying to see the mirrors fold and unfold on my command.

Now it was time to polish everything up. With a help from KiCad I designed the PCB, created custom parts for relays and prepared the files for PCB manufacturing. After that, it was just a matter of putting everything together – shopping for parts, ordering PCB, lots of soldering, PICAXE programming, enclosing the PCB in a case, and crimping the wiring harness.

As I am very pleased of how well the Power Fold Mirrors aka PFM module turned out, I decided to produce a small batch of 10 modules to put on eBay for other Zafira B owners to enjoy. And since Zafira B and Astra H have so much in common, the PFM module can be fitted to Astra H as well as the electrical side of mirrors is 100% identical to Zafira B. Here are the pictures of the PFM module and wiring harness that is ready to be fitted to the car.

I’ve put together a comprehensive installation and operation manual depicting and describing in detail all the steps needed to fit the module into the car you can download from the following links:
Installation guide for PFM module
Inštalačný manuál pre PFM modul

Here is a video explaining the operation and setup for the two modes of folding the mirrors.

Since the initial installation of the PFM module I retrofitted PEPS/Keyless to my Zafira so I uploaded another video showing that the module works with PEPS as well.

If you would like to buy the PFM module for your Astra H/Zafira B, I put a small stock for sale on eBay.

If you do not have eBay account, don’t want to/are unable to shop through eBay, or the eBay listing is out of stock please contact me at mironto@gmail.com and hopefully together we can find a way how to get the PFM module to you.

Sorry, out of stock.

2 Replies to “Opel/Vauxhall Zafira B/Astra H power fold mirrors via remote

  1. Hello sir. I bought from you one of the module and installed with the help of a guy that eat opel at breakfast. It was a workaround from him since my car had no deadlock and he just searching where to connect the green.. at the end Sucess. Very nice work.. take a bow. So for opel Antara you have some plans to do something? He has one he liked the ideea.

    • Hello Adrian, Thanks, I am glad you like the module. Regarding Antara, it’s difficult to create such a module for a car I don’t own. I would need physical access to the car to attach an oscilloscope and such in order to alter the module operation as needed note, Astra H and Zafira B are electrically identical cars, so it was possible to use the same module on both cars).

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