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I have an interesting electrical issue with my 2018 glc63s that has me stumped.
If I am driving in race mode and make any adjustment to the climate control (temp, fan speed etc), the car changes back into comfort mode.
I can change the dynamic drive mode back into race mode but then for some unknown reason, the traction control button does not function. I press or hold the button and there’s no function from it. But if i turn the car off an on, it all resets and runs as it should, until I adjust the climate control again.
It’s as if the climate control is sending a mixed signal somehow and affecting the drive mode and traction settings.
Mind you, the car goes back into comfort mode and drives fine with no issues which is what’s making me think it’s some form of electric issue.
Anyone experienced this or something similar and can provide some insight?
I have an interesting electrical issue with my 2018 glc63s that has me stumped.
If I am driving in race mode and make any adjustment to the climate control (temp, fan speed etc), the car changes back into comfort mode.
I can change the dynamic drive mode back into race mode but then for some unknown reason, the traction control button does not function. I press or hold the button and there’s no function from it. But if i turn the car off an on, it all resets and runs as it should, until I adjust the climate control again.
It’s as if the climate control is sending a mixed signal somehow and affecting the drive mode and traction settings.
Mind you, the car goes back into comfort mode and drives fine with no issues which is what’s making me think it’s some form of electric issue.
Anyone experienced this or something similar and can provide some insight?
As in the thread linked above, have you read out the error codes? That'd be the first place to start. Next thing, any aftermarket mods such as CarPlay modules etc. that could interfere with the OE systems? Any modification to the electrical system are likely the root cause of such odd electrical issues.
The interference idea is what I think is happening but I am not electronically minded at all so I have no idea how that’d work.
I haven’t read the error codes as I don’t have the hardware to do that and it’s not spitting out any codes through the dash.
Sorry, I should’ve added that into the original post. Yes, the car does an aftermarket CarPlay module which was installed by the previous owner. There was no mention from previous owner of this issue and I’d have no idea if this issue was present prior to the CarPlay module being installed.
Is it possible the CarPlay module is disrupting the electrical system of the car, mainly the climate control and centre console unit given the module is installed in that general area, and that’s causing the issue?
The interference idea is what I think is happening but I am not electronically minded at all so I have no idea how that’d work.
I haven’t read the error codes as I don’t have the hardware to do that and it’s not spitting out any codes through the dash.
Sorry, I should’ve added that into the original post. Yes, the car does an aftermarket CarPlay module which was installed by the previous owner. There was no mention from previous owner of this issue and I’d have no idea if this issue was present prior to the CarPlay module being installed.
Is it possible the CarPlay module is disrupting the electrical system of the car, mainly the climate control and centre console unit given the module is installed in that general area, and that’s causing the issue?
The interference idea is what I think is happening but I am not electronically minded at all so I have no idea how that’d work.
I haven’t read the error codes as I don’t have the hardware to do that and it’s not spitting out any codes through the dash.
Sorry, I should’ve added that into the original post. Yes, the car does an aftermarket CarPlay module which was installed by the previous owner. There was no mention from previous owner of this issue and I’d have no idea if this issue was present prior to the CarPlay module being installed.
Is it possible the CarPlay module is disrupting the electrical system of the car, mainly the climate control and centre console unit given the module is installed in that general area, and that’s causing the issue?
Yes, very possible. The poster in the other thread had an Android aftermarket unit that was causing the issue. It's very likely the CarPlay module. For all you know, the previous owner may have never even used Race mode in the first place. Some people just drive these things in Comfort mode the entire time.
Yes, very possible. The poster in the other thread had an Android aftermarket unit that was causing the issue. It's very likely the CarPlay module. For all you know, the previous owner may have never even used Race mode in the first place. Some people just drive these things in Comfort mode the entire time.
That or the previous owner might have had the issue but didn't know how to fix it or never thought of posting on the forums to ask what it might be.
Last edited by W205C43PFL; Aug 10, 2025 at 08:45 PM.
I’m going to reach out to the supplier who installed it as I had this noted when I purchased the car.
If no luck, I’m thinking I may need to temporarily disconnect and remove the module to troubleshoot and see if the car runs normally without it. If the module is removed and the car still continues with the issue, I can eliminate the module as the problem. On the flip side, if the module is removed and the car returns to driving normally, the module is the culprit and I’d need to work out how/why.
If I don’t connect my phone or ‘open’ the CarPlay screen, the car runs as it should. I don’t have any issues.
As soon as I open the CarPlay module on the screen (I need to hold down the ‘back’ button circled in my photo) and whether the phone is connected or not, this triggers something in the system and that is when I come into my climate control/dynamic drive issue.
Hoping with this extra info, someone might have a solution or suggestion on what to try next to work towards a solution.
If I don’t connect my phone or ‘open’ the CarPlay screen, the car runs as it should. I don’t have any issues.
As soon as I open the CarPlay module on the screen (I need to hold down the ‘back’ button circled in my photo) and whether the phone is connected or not, this triggers something in the system and that is when I come into my climate control/dynamic drive issue.
Hoping with this extra info, someone might have a solution or suggestion on what to try next to work towards a solution.
As suspected, the aftermarket CarPlay module is the culprit. It's probably mucking with the CAN bus and causing data corruption. The CAN bus is the main network in a car through which all the modules communicate. It's kinda like the WiFi or Ethernet network in your house. The issue is that these modules have to intercept the traffic that's intended for the Infotainment system and redirect it to itself, so that when you are pressing buttons and using the jog wheel, the car's Infotainment system is not reacting to it while the CarPlay module is active. So something is likely going wrong there.
Problem is these modules are generally not certified to make sure they work correctly and are not causing issues in the car. It's like WiFi and Ethernet devices. There's a standards body that tests and certifies them to make sure they implemented the standard correctly and are not corrupting the network. That certification process is expensive, so these cheap modules skip it as the market volume is kinda small and would increase the cost by quite a bit.
Your options at this point are to remove the module or live with the issue. If you know who made it, you can try to contact their support and see if they are aware of the issue and have a solution.
As suspected, the aftermarket CarPlay module is the culprit. It's probably mucking with the CAN bus and causing data corruption. The CAN bus is the main network in a car through which all the modules communicate. It's kinda like the WiFi or Ethernet network in your house. The issue is that these modules have to intercept the traffic that's intended for the Infotainment system and redirect it to itself, so that when you are pressing buttons and using the jog wheel, the car's Infotainment system is not reacting to it while the CarPlay module is active. So something is likely going wrong there.
Problem is these modules are generally not certified to make sure they work correctly and are not causing issues in the car. It's like WiFi and Ethernet devices. There's a standards body that tests and certifies them to make sure they implemented the standard correctly and are not corrupting the network. That certification process is expensive, so these cheap modules skip it as the market volume is kinda small and would increase the cost by quite a bit.
Your options at this point are to remove the module or live with the issue. If you know who made it, you can try to contact their support and see if they are aware of the issue and have a solution.
Funnily enough, I went to the business yesterday that made the product and because they didn’t install it, they were not interested in even offering any support or hearing out what the issue was. It was actually quite disappointing with the lack of customer service that they provided.
Funnily enough, I went to the business yesterday that made the product and because they didn’t install it, they were not interested in even offering any support or hearing out what the issue was. It was actually quite disappointing with the lack of customer service that they provided.
That is not at all surprising, as the issue could be due to incorrect installation, so the first place of support would be the business that installed it. They also likely have a support agreement with the maker of the product, so if the issue isn't due to the installation, they can escalate it. That's a fairly common process. For example I just had a new water heater installed at my house. If any issues arise with it, the first call would be to the plumber who installed it and not the manufacturer of the water heater. They can then troubleshoot the issue and rule out any problem with the installation first before pursuing a support/warranty claim with the manufacturer of the water heater. It's no different with other devices that require installation, because there's always the possibility that the product wasn't installed correctly and the manufacturer isn't gonna spend their time on troubleshooting somebody else's botched installation.
Last edited by superswiss; Aug 11, 2025 at 04:58 PM.
2014 ML63, 2018 GLC43, 1929 DB victory six sports roadster
The supplier of my CarPlay unit offered to send me a software update when we were having issues with it. I never had to do it due to fixing the problem in the units settings it was basically just me not having enough know how setting it up. All is good now though. So maybe see if they are willing to send you a software update.
The supplier of my CarPlay unit offered to send me a software update when we were having issues with it. I never had to do it due to fixing the problem in the units settings it was basically just me not having enough know how setting it up. All is good now though. So maybe see if they are willing to send you a software update.
you must have hacked my phone because I emailed the supplier about an hour ago asking if there was a software update that I may need to do
Digging up my old thread with some further info to hopefully get some insight to those who’re more electrical minded.
I have decided to remove the CarPlay module.
Whilst pulling it all out, I noticed a few questionable things.
1) they have tapped into the 12v socket connector with 3 wires labeled ACC, GROUND, ILL.
These will obviously need to be removed.
2) into the main harness going into the backside of the stereo, there’s a two wires which are connected to the CarPlay module but also connected into the harness. I’ve circled these two wires.
My question is, are those wires supposed to be there or can they just be pulled out?
I can post some more photos of those harness if it helps.
You best get a hold of the installation/wiring diagram for the module and reverse it. I haven't installed one of them myself, but based on the general understanding of how these work and installation guides I've seen, these things get spliced into the harnesses so it can intercept the video signal etc. and replace it with its own, meaning wires that used to go directly into the harness are disconnected and then connected to the module and a new wire goes back to the harness from the module. The wires in your second image for example look spliced, so just disconnecting them will most likely leave your stereo non-functional. You have to figure out how the original wires need to be connected back up, and the best way is to follow the installation guide in reverse.
You best get a hold of the installation/wiring diagram for the module and reverse it. I haven't installed one of them myself, but based on the general understanding of how these work and installation guides I've seen, these things get spliced into the harnesses so it can intercept the video signal etc. and replace it with its own, meaning wires that used to go directly into the harness are disconnected and then connected to the module and a new wire goes back to the harness from the module. The wires in your second image for example look spliced, so just disconnecting them will most likely leave your stereo non-functional. You have to figure out how the original wires need to be connected back up, and the best way is to follow the installation guide in reverse.
I’ve tried searching for that diagram with no luck unfortunately + the original supplier was not interested in helping as they did not install the product.
For those of you following at home, I took a chance and disconnected any wires that didn’t look OEM and put the car back together and it was all good. Happy days.
I bought a new screen off AliExpress. Very skeptical at first but quite satisfied with the product.
Proceeded to then pull the car apart, again, and re install the new screen I bought and it works flawlessly. Haven’t had any issues yet. Car runs as it’s supposed to with no climate control issues or dynamic drive issues.
Unsure if this can be accounted to the previous module (Linux) being subpar or, which I’m leaning to, the fact that the previous module had been wired into the quad lock harness and other wiring, instead of a plug and play set up.
Nevertheless, all sorted and moving forward.
Thanks for the insight and assistance all!
Last edited by palumbo23; Nov 16, 2025 at 04:21 AM.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
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