For those who are having intermittent or hard faults with your centre console window switch pack – don’t replace it – as it can be repaired. It is a simple fix.
The switch pack contains a multilayer board, microprocessor, 5V voltage regulator, 12V feed, three “data” wires to the BECM and the switches.( PU is 12V, B is earth RU is 12V feed for the lamp from the BECM, R,OG, and LG and the data/signal wires. DON'T try to test any pinouts with the pack connected to power - there is a very high chance you will fry it - just check you are getting 12V input from the male connector, and for those with a bit more bravado check for 5V from the regulator on the board.
The switches are open design with no rubber boot on them to keep out moisture or contamination. The switches have an open contact and this contact is on the surface of the board – similar to computer keyboards.
Unfortunately, the drinks holder is above the switches – so any drink that is split goes into the switche pack and flows across the board. - and the contacts become contaminated. Similarly, if you leave the sunroof open during rain, the water will corrode the contact area. Because the switches operate on low voltage at 5V, the condition of the contact surface is critical in order to send a switching signal to the microprocessor.
Also if you are soaking wet from water sports or rain and operate the switch pack it is likely the water will migrate onto the board from your dripping arms and fingers.
Firstly try spraying ELECTROLUBE EML contact cleaner/lubricant into the side of the switch that is not working – i.e. onto the circuit board. Do not use standard contact cleaner because it supercools the contact and then water vapour condenses onto the contact surface and can lead more corrosion ( unless you then use oiless compressed air to dry)
If the EML contact cleaner does not work then the next step would be removing the switch from the board, cleaning the contact and reattaching. For me the EML worked and I did not need to remove the switch.
When re-fitting the switch pack I suggest covering it in cling wrap and then installing the now watertight switch pack into its housing – this will ensure liquids cannot enter the switch pack again. The rocker switches work fine with the cling wrap on – just looks a little untidy.