[Goandiaries]

I have a December 2020 manufactured XUV300 with current odo close to 48k kms. At the time of purchase, I installed the official Mahindra LED scuff plates accessory through the dealer. The power for this accessory was sourced from the cabin lamps wiring with a separate fuse (which I learned after the issue to be honest) – which switches off once I start or lock the vehicle. Normally, when the cabin lamps are in auto or door mode, the lamps in the cabin turn on and off while opening and closing the doors, respectively. The manual switches, on the other hand keeps the lights on while you are inside the car and turns off automatically when you lock the car.

Now to the symptoms: I remember the cabin lamps in my car working normally atleast till the end of March 2023. Fwd to mid-April, after a 400km trip, park the car (power off the dashcam) and unlock next morning only to find the battery dead within 24 hrs of the trip, with a battery voltage of 9.9V. RSA arrives within an hour to jump start the car with their battery pack, and I charge it for an hour by driving around highways. Meanwhile knowing that I had no other extra fittings in my car other than the dashcam and the LED scuffs, that could possibly drain the battery, I removed the power supply to the LED plates. However, the battery kept draining and eventually was proved useless as it did not hold cranking voltage even for 2 days without driving. The battery was draining even when it was not connected to the car! This proved to be the first major issue in the car which impacted the battery for worse and I had to replace it.

The issue: I realised that the LED scuffs did not turn off while holding the door switch and locking the car. I was told by the service that they have connected the LED scuffs to the cabin lamps and the LED goes off around 10 mins when the doors are open (which I have noticed sometimes while washing the car) and similarly goes off while locking the car as well. To avoid taking chances on the new battery, I removed the separate 5A fuse in the LED scuff wiring. And thought that I will check the wiring during the 50k service. One fine day my son leaves the rear cabin lamp on in a basement parking of a mall, and I notice that the lights do not turn off while locking the car. Upon returning home, checked the cabin lamps and realized that the lamps in manual mode did stay on for over 20 minutes that I checked. I strongly suspect that this issue has cropped up at some point of time late march or early April, and this slowly killed the battery. I did not notice because the cabin lamps are usually in door / auto mode which works PERFECTLY fine till now and LED scuffs are not visible with closed doors.

Here is a video comparing a normal and the affected vehicles’ lamp functioning.

Cabin Lamp Issue

Though I have informed the Mahindra service personnel who looks at electricals (looks like I provided them a new issue), I thought it would be a good idea to figure out the possibilities for such a malfunction. Experts here can provide your inputs please!

Additional info: Here's the fuse box information of my car. I don't see a separate fuse for the room lamps.


I did check the Ssangyong Tivoli’s wiring manual (considering that most of the wiring for existing features are similar - I also assumed this looking at the layout of the fusebox in both) – but I couldn’t understand about where it could go wrong with the help of the circuit diagram. Am attaching a pdf of the interior lamps circuit here.
Interior Lamps.pdf

[Omkar]

Cabin light staying on is not uncommon, but your case does seem a bit strange because of the added scuff plate. I'm guessing that you had the scuff plates installed back when the car was new and the issue that you are facing is more recent.

The common reason for the cabin light staying on would be the door latch/actuator might've gone bad. Maybe the door isn't getting closed properly. Did you notice a door-ajar warning on the MID? That could lead to the cabin light staying On.

But if that's fine and the fuses and relays are fine too, and you still have a battery leak then there might be some other electrical issue which would need a proper electrician to inspect.

Please do update what the electrician at Mahindra says about the whole thing.

[Goandiaries]

Originally Posted by Omkar

Cabin light staying on is not uncommon, but your case does seem a bit strange because of the added scuff plate. I'm guessing that you had the scuff plates installed back when the car was new and the issue that you are facing is more recent.

The common reason for the cabin light staying on would be the door latch/actuator might've gone bad. Maybe the door isn't getting closed properly. Did you notice a door-ajar warning on the MID? That could lead to the cabin light staying On.

But if that's fine and the fuses and relays are fine too, and you still have a battery leak then there might be some other electrical issue which would need a proper electrician to inspect.

Please do update what the electrician at Mahindra says about the whole thing.

Thanks for the reply Omkar! Yes, the scuff plates were installed at the time of delivery of car in 2021 Jan. There were no issues till recently. However, I did notice that sometimes the scuff plates used to stay off/glow very faint (randomly, on all 4 sides) even while opening the door. I dismissed it as failing LEDs. Once while I removed the floor trim to fix the dashcam wiring, I noticed that the LEDs intensity was back to normal! Again, this happened somewhere in the month of March 2023 and I did not give it much thought!

There's no issue with door actuator anytime. Whenever the MID says the door is open, it is indeed open.

Regarding the fuse, I did not open and check the memory fuse yet, since all other functions routed through the PF2 fuse (please refer the fuse box image in the original post) are working fine. Do you think it is a good idea to remove it and check for once?

[krishnakumar]

Originally Posted by Goandiaries

One fine day my son leaves the rear cabin lamp on in a basement parking of a mall, and I notice that the lights do not turn off while locking the car. Upon returning home, checked the cabin lamps and realized that the lamps in manual mode did stay on for over 20 minutes that I checked.

In the car where this is working properly (in the video) the light turns off immediately. However that is not the case usually by design. I see they have added some footwell lights as well to this. Is it possible they have changed the module or wiring while doing this mod?

I’ll check in my car and let you know.

[srini1785]

Originally Posted by Goandiaries

I have a December 2020 manufactured XUV300 with current odo close to 48k kms. At the time of purchase, I installed the official Mahindra LED scuff plates accessory through the dealer. The power for this accessory was sourced from the cabin lamps wiring with a separate fuse (which I learned after the issue to be honest) – which switches off once I start or lock the vehicle

Is this a standard feature from Mahindra or an after market feature?. Since the wiring harness needs to be original in case of a standard OEM part. If it is some aftermarket accessory then the guy doing the wiring may have sourced the power from some other terminal/fuse or wherever.

Originally Posted by Goandiaries

I did check the Ssangyong Tivoli’s wiring manual (considering that most of the wiring for existing features are similar - I also assumed this looking at the layout of the fusebox in both) – but I couldn’t understand about where it could go wrong with the help of the circuit diagram. Am attaching a pdf of the interior lamps circuit here.

From the circuit, all lamps are controlled by switches to the ground. Its typical of circuits from that region (Korea/Japan) where most wiring are "sinking" or NPN type. I have highlighted one such circuit which is the passenger courtesy lamp for ref. Only problem with Sinking circuits is that if there is an alternative path to ground then the switch looses its control.



Does the lamp which is the subject of interest the same as what i have shown in the below circuit?.

[Goandiaries]

Originally Posted by krishnakumar

In the car where this is working properly (in the video) the light turns off immediately. However that is not the case usually by design. I see they have added some footwell lights as well to this. Is it possible they have changed the module or wiring while doing this mod?

I’ll check in my car and let you know.

Please let me know how it is in your car! I was under the impression that the cabin lamps works like this, since even the manual says so. Please refer to the section 8.8.2 under features and control / interior lamps in your manual. Not sure if there was a change in functions later? Because I saw another car (relatively new one) where the interior lamp switched off after 20-30 seconds after locking the car.

Originally Posted by srini1785

Is this a standard feature from Mahindra or an after market feature?. Since the wiring harness needs to be original in case of a standard OEM part. If it is some aftermarket accessory then the guy doing the wiring may have sourced the power from some other terminal/fuse or wherever.

The LED scuff plates are not a standard feature of the car. It is just an official accessory, sold by Mahindra and I purchased it along with the car. They installed it before delivery of the car. However, I was not sure about the wiring - till the unfortunate event!

Originally Posted by srini1785

From the circuit, all lamps are controlled by switches to the ground. Its typical of circuits from that region (Korea/Japan) where most wiring are "sinking" or NPN type. I have highlighted one such circuit which is the passenger courtesy lamp for ref. Only problem with Sinking circuits is that if there is an alternative path to ground then the switch looses its control.

Attachment 2457540

Thanks for this info. Do you mean to say that if the original wiring was tampered, then maybe it is now getting grounded somewhere?

Originally Posted by srini1785

Does the lamp which is the subject of interest the same as what i have shown in the below circuit?.

Attachment 2457541

Partly yes. The front spot lamps (immediately left, highlighed in blue) are also part of the problem. The center lamp is in the center of the roof while the front spot lamps are in the front, like shown in the video. They all work as intended in Auto mode. They just stay on indefinitely in manual mode, which was not the case earlier!

[srini1785]

Originally Posted by Goandiaries

The LED scuff plates are not a standard feature of the car. It is just an official accessory, sold by Mahindra and I purchased it along with the car. They installed it before delivery of the car. However, I was not sure about the wiring - till the unfortunate event!

"Official accessory" : Another word for warranty void parts?. If it is official then Mahindra should have left an wiring provision for center roof light. Any other case, the dealer must have made some non standard wiring provision.

Originally Posted by Goandiaries

Thanks for this info. Do you mean to say that if the original wiring was tampered, then maybe it is now getting grounded somewhere?

May be. As i said before with sinking circuits, all it takes is a path to ground since the positive always present on one terminal.

Originally Posted by Goandiaries

Partly yes. The front spot lamps (immediately left, highlighed in blue) are also part of the problem. The center lamp is in the center of the roof while the front spot lamps are in the front, like shown in the video. They all work as intended in Auto mode. They just stay on indefinitely in manual mode, which was not the case earlier!

The current flow path is as per the circuit below.
Page - 1

Page - 2


In the above, the red is the positive line and depending upon the position of the switch, the return path is either the blue or green line. The Brown White (BrW) and Black (BL) bring the 12V to the lamp and there must be continuity between pin 3 of the "Center room lamp" and Pin 4 of the FRT room lamp as per circuit diagram. Depending on the position of the door, the door switch (DR SW) is open or closed and the path to ground is through the Light Brown (LBr) or Light Red (LR) wires. Further, BCM (Body control module) controls the return path through terminals C201- 1 to 20.

If you are handy with a multimeter you can check the above points. It would however be difficult since all these would be concealed wiring and you don't want to mess with a new car. So i would suggest that you take this matter further with the ASC only.

[Goandiaries]

Originally Posted by srini1785

"Official accessory" : Another word for warranty void parts?. If it is official then Mahindra should have left an wiring provision for center roof light. Any other case, the dealer must have made some non standard wiring provision.



May be. As i said before with sinking circuits, all it takes is a path to ground since the positive always present on one terminal.

Thanks for your detailed explanation Srini. I will take it up with the ASC (already been behind them) One more information, I just checked the sun visor lamp, the circuit on the right. When left on and locked, it doesn't go off as well. Just stays on. Looks like there's an issue in that entire line!

[Goandiaries]

Originally Posted by srini1785

"Official accessory" : Another word for warranty void parts?. If it is official then Mahindra should have left an wiring provision for center roof light. Any other case, the dealer must have made some non standard wiring provision.

Final Update: Issue Fixed.

The cabin lamp issue ultimately was solved when the LED scuff plate wiring was completely removed from the main wiring.


As you can see in the picture above, the black wire (for LED scuff plates) was connected to the cabin lamp wiring (by splicing the original wiring) by the dealer. Down this line, they installed a 5A fuse. I'm not sure what went wrong in this wiring that resulted in this issue. They suspect that the LED scuffs may have shorted, and somehow started draining the battery by keeping the lights on! Pulled this wire out, sealed the lines with taping and closed the A Pillar. Now the lights are working as it should.

Advice to anyone interested in LED scuff plates in XUV300 - just stick with the non-LED scuffs. The official accessory actually doesn't cost much so many just throw it in like me, but in hindsight I feel it is a sub-standard accessory. I changed one of the rear scuffs plates under warranty. And within a year after that - there were issues with them intermittently. I didn't want to fix it again and instead just used it without the LEDs. But the wiring ultimately killed the stock battery in 2.5 years!

Thanks for the support here, srini!