Alfa Romeo Brera/Spider Window Switch Repair

Frameless windows; what a joy.

Whilst I enjoyed the frameless windows on the Brera and my MiTo, what I didn’t enjoy was the endless calibration of the anti-pinch system after a battery disconnect or if the anti-pinch system got a little confused every other month and thought that they air was impeding its path to close. It isn’t much effort to retrain the system into the correct values, however it becomes a completely different story if the window switch is signalling the wrong up/down motion and causing it to stutter and not complete a full relearn cycle. Unfortunately second-hand window switches are going upwards of £200, and new ones are costing ~£300 as well; so it’s not a cheap fix for more than an annoyance.

Even though the MiTo sold in many more numbers that the Brera or 939 Spider, window switch faults are nowhere near as common as you’d expect from them. MiTo window switches are in common abundance so I purchased one to strip down to view the differences between that and a 939 series one. Although they looks similar, and their internal function is similar, the internal construction and PCB routing including pinout is wildly different so do not plug a MiTo window switch into a Brera/Spider and expect it to work!

I’ve found that a normal clean out of the conductive elements on the PCBs are the main sticking point on the 939 series of window switches, and a light cleaning of the PCB contacts and conductive elements is able to fix 99% of intermittent signalling. I’ve had a fair number of window switches as spares that I purchased, and all of the conductive elements have had some form of corrosion causing poor signalling.

Due to the poor signalling, it seems that people put more and more pressure on their window switch buttons in attempt to increase conductivity. This works for a short period of time, however this increase of pressure on the conductive elements means a higher pressure on the buttons and button pivots, causing the buttons to split down the centre and the pivots to shear off after a period of time. I’ve since designed and can refit new button mounts/pivots which are comparable strength to the originals, if not stronger due to the materials used.

Since these inserts need to be installed with the window switch stripped down, and some minor modification required to the switch, the switch must be sent in to have a new pivot insert installed. It is recommended to install a new button as the same time of the insert, as if a pivot point is sheared then a crack has also begun forming down the centreline of the button – unfortunately new buttons are not easy to come by, and as such are fairly expensive to replace.

We have developed a test bench for all of the functions of the Window Switches, with realtime feedback for buttons pressed and their expected and actual values, meaning a thorough test can be completed both before and after teardown to emulate the signalling the Window ECU would receive on the vehicle.

Clientele: Alfa Romeo 939 Series

Compatible Engines: All Engines

Compatible Cars: Alfa Romeo Brera, Alfa Romeo Spider (939)

Release Date: February 1, 2021