Hi,

 

My Octavia Electric Window switches were faulty. There was no back lighting on any of the switches, the passenger side did not have down or one shot down and the driver side up was intermittent. The rear windows were fine for up down and one shot function. The rear window child lock did not operate, but it had back lighting.

 

I decided to open it up to see if it could be repaired.

 

Getting it apart is quite tricky as the latches that hold the unit together are very tight. I used some butter knives inserted along the sides to release the latches, but there is a risk of damaging the latches permanently.

 

Once you have released all the latches on one side, you can move to the other latches and hopefully, this will allow the switch unit to pop apart.

 

Once open, the corrosion was evident.

 

Some of the "lead through" holes in the PCB were corroded and therefore open circuit.

 

In the picture above, the large copper areas are directly under the back lighting LED for each switch, and each area had a lead through, which was open circuit. In total, there were 7 lead through connections for the back lighting which were open circuit. I also found 4 bad lead through connections for the passenger switch functions which needed new wires fitting.

 

 

In order to fix the connection, I drilled a 0.7mm hole though through the PCB next to each back light LED, so that the hole would connect the copper tracks on both sides of the PCB.

 

I then inserted a single strand of 0.1mm copper wire (a single strand from a flexible cable) in the hole and soldered it on each side of the PC to re-make a new lead through.  You have to ensure that the wires are kept a s close to the LED's as possible, as they could interfere with the tactile switch frame that sits on the PCB.

 

This was a difficult job and I am not proud of the quality, but it serves its purpose.

 

The rear window OFF button uses conductive rubber pads to bridge two copper tracks. This function was restored by cleaning the PCB with a fibreglass pencil and cleaning the conductive rubber with some isopropyl alcohol (tape head cleaner fluid or vodka at a push!).

 

The layout of the connections to the connector are:

 

Pin 1 - Rear Windows Lock Off (command to ECU)

Pin 2 - Rear Windows Lock ON (Orange LED) 

Pin 3 - 12V for Backlighting for all switches (Green LED's)

Pin 4 - Ground (0V)

Pin 5 - Front Left Window

Pin 6 - Front Right Window

Pin 7 - Rear Right Window

Pin 8 - Rear Left Window

Pin 9 - Not used

Pin 10 - Not used

 

The four functions of each switch (UP, one shot UP, DOWN & One shot DOWN) are determined by the resistors on the PCB. When a particular resistance is measured by the ECU between the relevant pin for that window and ground, the ECU performs that function. 

For example, when you press the right front button fully forward, you get One Shot DOWN function, this is because the switch will connect a particular resistor between Pin 6 (Front Right) and Ground. The ECU interprets the resistance and translates this to the required function.

I didn't measure what the different resistance were for the four functions per switch.

 

All windows perform their correct functions and all back lights now work.

 

 

Hope this makes sense

 

Russ

 

 

Hi

 

Forgot to add the picture of using the butter knives to separate the grey switch carrier from the main body. The fit is very tight, and you need to get three knives in each side, if you have that many knives! the pink lines indicate the holes in the body where you can just see the five retaining lugs per side, two at each end and one in the middle.

 

Russ