The clock spring is a rotary device that makes the electrical connection between your steering wheel buttons/horn and the rest of the car's electronic control unit. It is placed just behind your airbag at the center of the wheel. Unfortunately, this element may fail after a few years even if you did not drive a lot with your car. It is a plastic band containing several electrical tracks that wraps/unwraps when you turn your steering wheel. Most often, the clock spring will fail due to broken tracks or a broken connection between the band/tracks and the connector to the circuit board.

VW is known to have a lot of issues with this component; this just happened with my Tiguan 2.0 (2016).

Common symptoms:

• The airbag light is on
• (and) steering wheel buttons not responding
• (and) horn not working

If you have all these problems at once, it is highly sure you are running into a clock spring issue. If you have an OBD scanner, you can run a scan to check whether your airbag is complaining about "high resistance" (meaning connectivity is broken).

This repair requires some basic mechanical skills and some skills with soldering/desoldering. Keep in mind that a replacement unit for Tiguan 2 is about 400$ (and it must be recoded with the appropriate OBD programmer) so this may be worth trying. And at the time of writing, there is a lot of delay in the production such that a brand new clock spring is not easy to find.

This guide also applies to Skoda which shares the same components on most models. Clock springs in other brands may look like that but I have seen that some car manufacturers are using a different mechanism with a longer strip without the rubber rings and looking more like a spiral spring. They all share common failures which are typically occurring at one end of their internal electrical ribbon with a clear break due to mechanical traction and poor assembly.

Torx TX55 bit, Torx screwdrivers, flat screwdriver, soldering iron, desoldering pump/solder wick, solder, adhesive, multimeter (continuity/testing mode)

Very important: before doing anything on the wheel, disconnect the battery and wait 15 minutes.

These steps are usually similar on different models, I highly recommend that you check videos on Youtube so you see how it's done. Golf, Touran, and Tiguan have all the same kind of design.

But I still give here the main steps. After you have unplugged the battery, you need to remove the top plastic cover behind the wheel. You must insert either a thin but hard plastic piece into the seam or a flat screwdriver, be careful to not scratch your cover. By slightly twisting your tool, you should be able to pry open the cover and flip it to the back.

Then, time to unlock the airbag. Turn your steering wheel by 90° on the left side. You will see behind the steering wheel that there is a hole that gives you access to a spring that locks one side of the airbag. This is best done by using a flat screwdriver (~1 cm head) that you horizontally insert into the hole until you hit the spring mechanism. Then move the head downwards by raising the screwdriver until you unlock the spring (it may make a small 'click'). Repeat the operation on the other side by turning your wheel again, this time 90° on the right side.

At this point, the airbag should be unlocked. There should be two sets of cables, one to a big yellow connector and a smaller connector on the side of the steering wheel. Unplug both and you should be able to take them out of the airbag unit. Be careful with this component, avoid shocks, and immediately store it in a safe and clean place where it cannot fall.

Recenter the steering wheel before proceeding. The steering wheel is fixed to the steering column with a large Torx-like bolt (VW used a triple-square bolt). Fortunately, this is compatible with a Torx T55, and in practice, this works very well and you don't need the special VW bit. Don't use an Allen key though, this would slip and ruin the bolt.

Remove the bolt but don't extract the wheel yet. I recommended that you make a picture of the wheel center at this point, you will notice that there is a small vertical groove on the inner (dented) tube and another one on the outer area. You will need to set the same alignment when you put the wheel back at the end of the repair. Lines can be slightly off so that's where the picture can be handy.

Now you can simply pull the steering wheel towards you and set it aside. You will now be facing the object of this instructable, the clock spring which looks like a circular plastic part with a connector on one side of the disk, hence its name.

With Torx screwdrivers, remove the screws that are holding the clock spring and the lower plastic cover. Then remove the smaller screws that are just above the two previous ones. You will need to remove the bottom main cover of your steering column (the part held by my finger on the pic), there's another Torx screw on its lower face, near the location where you would have your left knee. Locate it and unscrew it. The whole plastic cover should then freely move.

Various cables are connected to the clock spring. The first one is the big yellow connector on the lower left. You must first unlock it by pushing the red switch down, then unplug the whole yellow block by pulling it downwards.

Some connectors are held by small plastic grips (check the pictures in the next step to have a closer view), you must slightly bend them to ensure the connector can be unplugged freely.

On the top left, there's a simpler connector that you can disconnect by moving it upwards. On the right side, in the middle, is one connector that must be pulled to the right. The same applies to the lower right connector that must be pulled down.

Under the clock spring, there should be a large connector that you must pull downwards too. This one is quite stiff, be careful to not put too much pressure and break wires.

When all wires have been disconnected, the clock spring can be extracted.

The clock spring is made of black plastic with a rotating part in the middle that holds the connector (to the airbag). The various connectors to the PCB are visible on its sides. The back of the clock spring does not reveal anything interesting.

The first step will be to remove the back cover of the unit and access the PCB. If you look on all sides of the clock spring, you will see some plastic clips, there are like 4-5 of them. Pry them open one by one - pay attention to not breaking them - and you should be able to remove the cover and access the PCB. A guitar pick or plastic tools used to open smartphones may be handy for this.

First visual inspection of the PCB: does it look clean? are there any traces of burn? do components look ok? There is a capacitor at the bottom of the PCB that could potentially fail (leaking traces or bulged top). If the PCB looks ok, you can proceed with the next steps.

If you suspect the PCB has an issue, this is unfortunately getting out of the scope of this Instructable and would require deeper analysis and diagnostics with a multimeter, starting with the diodes, resistors, etc.

My device was assembled by Valeo in August 2016 but failed less than six years after a very moderate usage (car has only 50000 km).

Before proceeding, I recommended that you check the video of someone who had disassembled the clock spring. Watch it closely as it may help you to understand how this thing is made.

To access the area where the failure is likely to present, you need to remove the front of the rotating part. To do this, you will need to pry open some plastic clips that are present on the inner side of the "tunnel" and hold the front disk. I used a thin flat screwdriver to open them, starting from the back of the clock spring and pushing them towards the front (arrows in picture). I recommended doing this while holding the front side with your finger or putting the front on a table. You don't want to let the plastic strip fly away at that point, not that it's impossible to set it back but it's always easier to see how things were arranged before proceeding.

Gently extract the front circular plastic panel (the piece with the airbag connector), this should reveal the inner of the clock spring with the rubber rings and the flat electrical band wrapped around the center part. With the front of the clock spring towards you, try rotating the connector clockwise, then counter-clockwise to see how it works.

There is one extra piece that must be removed to fully access the rotating part. The outer part of the clock spring "cylinder" is attached to the main cover with some plastic clips again. Pry them open and you should be able to remove them. See the expected result in the last picture.

In my case, the problem was quickly found. One end of the plastic strip (the one linked to the PCB thanks to a connector with several pins) was completely broken with copper tracks ripped off. No wonder neither the horn nor the buttons would work as no electrical connection was present anymore. It is also a shame to see how this important device (I estimate the horn to be vital) is badly assembled: just two melted plastic dots on the strip to hold it in place and thin copper tracks directly point-soldered on the underlying pins (third picture). The strip is supposed to be inserted into this connector (4th picture) that is sending part of the tracks to the PCB and some traces to an external connector.

To make a full diagnostics, you should check the following

• Is the strip still correctly attached on each side (PCB connector and airbag connector)?
• Is the strip damaged?
• Is the plastic on some tracks damaged and copper exposed to air?
• Are there some copper particles wandering in the rotating assembly?

A multimeter, set on continuity mode, is very handy to check the connectivity if the assembly does not look broken. One probe is set on one pin present on the end connector (going to PCB) and the other probe is used to scan the pins on the airbag side. A beep will indicate that the track is not broken. If some copper is exposed on the track, you may try to add some varnish to avoid the copper to oxidize and having potential shortcuts.

In my case, as the strip was completely separated from the rest, soldering is the solution. Fortunately, this can be easily repaired as we will see.

To repair the connector where the strip is attached, it is necessary to separate it from the PCB. Unfortunately, its pins are directly soldered on the PCB. Flip the clock spring and locate the soldered pins, unsolder them either with a pump or some wick. When it's done, you should be able to fully remove the connector arm (2nd picture), it requires some force to unlock it as it's held by some plastic clips.

You will then need to clean all the remaining copper on the pins (3rd picture). I used a small screwdriver to scratch them. It is not a problem if the only thing that remains is a small copper dot it will make soldering easier. But you need to get rid of all damaged and thin copper tracks that could touch other pins and make shorts.

When it's done, take some solder and put a solder blob on each pin. This will allow a better soldering job afterward when you attach the strip back again.

Fortunately in my situation, the strip was broken just at its very end such that only a tiny portion of the strip was damaged. I took a pair of scissors and made a clean-cut, removing about 1mm of the damaged strip (first diagram). Then, gently remove the plastic covering each track with your hot iron tip.

Take your time, don't put too much pressure on the iron as you don't want to damage the tracks. Remove the plastic layer on each track until you reach a sufficient length for soldering (about 3-5 mm). It is not necessary to have perfectly clean tracks but the copper must be sufficiently exposed to allow you to put a small blob of solder on each track. Do this on both sides. In the end, you should have a strip that looks like a "fork".

It is extremely important that you do not twist the strip and that it is attached the correct way. Check the spiral picture to see how the strip should be wrapped. To avoid issues during soldering, I recommended that you block the connector somewhere with a light grip plier, adhesive, or whatever is suitable. You will just need to manipulate the strip with one hand and with the other hand, you'll be able to use your iron to solder it track by track (this is where the pre-soldering job on tracks and connectors is a life saver). Normally just applying the iron tip on the track should be sufficient to merge the solder blob on the connector.

As the whole soldering job is not meant to support mechanical stress, I added a good strip of yellow adhesive as you can see in the last picture. No need to put tons of it, you just want to avoid the strip from being ripped off again. In all cases, this is better than the poor job that was done initially with these melted plastic dots that were pretty weak.

I highly recommend you check each track's continuity by using the multimeter, one probe touching the solder and the other touching each pin on the airbag connector. The multimeter should beep for each pin. You can also verify that you don't have shorts between pins.

This is a step that is not that easy as you need to figure out how the strip is supposed to rotate. Here is some useful information:

• On my model, the spring clock, when centered, can make about 2.5 turns on left, and 2.5 turns on the right.
• You must always keep things symmetrical as your clock spring is supposed to rest in the center position on your steering wheel. If you can only make one turn on the left but 3 turns on the right, then it's unbalanced and will fail.
• The rotary part has a short thread on its back. I recommend that you try to turn the whole cylinder to the left, then to the right (let the strip end follow the whole displacement) until it blocks. After a while, you should be able to find the "center" and determine how many turns are required to set it to the maximum on each side.

It took me about 10 minutes playing back and forth to get a feeling of how it was supposed to move and work. I think the best way is to turn it counter-clockwise to the maximum, then back by a dozen degrees, and then wrap the strip as described. You can then reattach the strip connector on the left side.

It should form a semi-loop where you can place the first white rubber ring. If the loop is not big enough, rotate the cylinder a bit. One important note: rings have one side with some teeth, while the other side does not. The teeth must be placed at the bottom such that when the main cylinder (which has some gear on the bottom side) is rotated, the rings will follow the gear.

Continue rotating a bit, the first ring should "track" the back of the strip. You can then insert the 2nd ring, rotate a bit, then insert the last ring. They must be placed such that they are evenly spread along the strip.

Optional: you may want to add some white grease to avoid friction between the strip layers.

Again, I recommend that you watch the video of the disassembly.

When you are satisfied with your wrapping job (test it several times, left, right, recenter it...), you can put the cover over the center part. Then turn the clock spring and don't forget to resolder the pins on the PCB. The rest of the clock spring reassembly should be easy as you just have to put the cover in place with the plastic clips.

Put the clock spring back in place on the steering column, check that all connectors are reattached, place the bottom cover back, and replace screws. When done, recenter your clock spring (such that you could make 2.5 turns on left, 2.5 on right).

Place the steering wheel on the column, this is where you must correctly align it with the gears (remember the small grooves on the inner and outer rings?). The airbag connector should be right in the middle. Put the "Torx T55" screw back in place and then reattach the airbag with the yellow connector and the smaller connector.

Reconnect the battery, then make a test. If your horn is working and buttons are back successful repair!