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Bought mine from a UK eBay seller as shown on the clip near the beginning of the video or search for VW Mk 7 Golf R exhaust valve delete. It's sold for VW but also works on our R172 SLK55 as it uses the same valve actuator.

@@leew88 thank you 🙏

Thanks for this info, mine works as you explained but the annoying thing is you have to stand near the door handle with the button pressed. I'm looking to buy and fit the X car style roof module (not Smart Top) and looking to do a video of the installation and review of it later on this year.

@@paullynch6977 I was waiting for someone to notice that.. 😂

Could be a number of reasons, the main battery maybe past it's life as I had the exact same issue when I charged my original main battery overnight the start\stop worked literally for 1 or 2 stop\start cycles before it disabled again (voltage drops below its working threshold). The small battery behind the passenger seat (UK right hand drive) is only there for powering the auxilliary equipment whilst stop \ start is in operation. You have to partially remove the cover in order to get to it, these are held on with a few screw \ pop-up clips, storage netting also needs to be unclipped as well. The battery is held on with a bracket and nut should you need to remove it. Measure the voltage of this small battery it should read around 12.5v - 13v in an idle state with engine engine off, you can try charge this overnight and see what happens, but most likely it will be the main battery causing your issue, how old is the battery?

Many thanks for your reply 🙏 I guess it could well be the main battery as you suspect as it is pretty old. Would it be OK to use a generic battery I.e. not one from a Mercedes dealer as these are extremely pricey? Kind regards.

@@Farrelbf There's a misconception that batteries purchased through the dealer is superior to all, most are true with the exception of a few items and batteries are one of them. Mercedes batteries are simply rebranded Varta AGM batteries which you can buy via independent online retailers at half the price, the exact one shown in my video 12v 80ah AGM type bought from UK's Tayna Batteries. Of course you don't have to go for Varta, other well known brands such as Exide, Yuasa, Bosch are just as good, just make sure it's an AGM start\stop battery of the correct AH capacity and not a generic battery which was fitted on mine causing all these issues.

@@leew88 fantastic - thanks Wilson! I am actually in Cape Town SA but pretty sure I will have no problem sourcing the correct battery specification exactly as you suggest🙏

Thanks for your kind comments, yes completely forgot to protect the covers was so ingrained doing the video.

Engine will hold back and lose power at around 5000rpm. EML light will not illuminate only soft fault codes are stored which can only be read with a OBD2 diagnostic reader similar to the one I'd used. Sometimes when one actuator fails it will cause the opposite side actuator (working one) to cycle between open and closing as it tries to sync up with the faulty side, so if you hear this continuous cycling when you turn the ignition to no 2 without starting the engine then the other side actuator is faulty. Bare in mind you may also have other symptoms like short or open circuit fault codes which may not be obvious without a code reader, hope this helps.

@@leew88 thanks for the info! One other question. If one goes bad, I've read that when the key is in the ON position but car not actually started, the flap actuators will make whirling sound as the good one tries to sync with the bad one. If both are good, do they still whirl when car is on but not started?

@@youngp4116 If both are good you shouldn't get any constant noise other than the initial flap movement pre-start.

Hi Christina, I have the exact same idea as you, however I'm kind of fortunate that my stop\start never worked since I purchased this vehicle 6 months ago even though the ECO button green LED is always on and the ECO8\ECO4 cylinder de-activation and brake HOLD function still works as intended. I've researched into this quite a bit and found that the previous owner had fitted a bog standard 12v 80ah flooded battery (rather than the AGM version), so the car has intelligently recognised this situation and disabled the stop\start function whilst keeping all the other functions to work as intended. The 12v 10ah auxiliary battery behind the passenger seat had also been swapped out but I don't think this is the reason it has disabled my stop\start as they had installed the correct AGM 12v 10ah replacement. I will be doing some coding \ programming videos in the near future of some of the features which I've activated already, so I'll take the opportunity to see if this can be coded out without effecting the other functions, watch this space.

@@leew88 Thanks a lot for your reply. Very interested to see your future videos!

Yeah no probs tag along with your MX-5 😁

Trip around the Alps, would be even better...!! 👍