Extra reversing light C5X7, connect?

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fikse
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Extra reversing light C5X7, connect?

Post by fikse »

Working at mounting tow bar and when at it, a xtra reversing light. Original reversing lights are a joke, in combination with a camera that is useless in the dark, I really need some more lights. As its only legal to have a max of two reversing lights, I will remove the bulb or dismantle the reversing light at one of the sides, via Diagbox.

But. How to connect a simple LED light? It's a plain LED lamp of decent quality, consumption is said to be 12W, I guess 15W IRL.

I was first thinking of just hook into the wires for the trailer connection, but thinkering about it this might not be an good idea, as the reversing module for the tow bar will be programmed into BSI, and I belive must have some auto-sense-thing to know when a trailer is attached, as the module handles both LED and filament at the trailer, and it does not have any microswitches to turn off rear foglight or whatever. So... Can I try the nasty way just to remove the bulb in one of rear lamps, and connect this LED lamp? Or will a 12-15W consumption be sensed as a faulty filament, or will BSO dont understand the LED and assume there is a fault anyway?
So my option is to do it the proper way with relay with signal from any of the rear lamps, and if so what is a good scource for 12V power? The model is 2014 CrossTourer, 2litre auto.
IMG_20210310_200714.jpg

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GiveMeABreak
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Re: Extra reversing light C5X7, connect?

Post by GiveMeABreak »

The reversing light circuit is sensitive to LEDs and will record errors in the BSI and cause erratic behaviour. I replaced my reversing bulbs with brighter LEDs on my X7 for the same reason, but got notified by drivers on occasion that they were flashing! Also, when looking at the BSI fault logs it was flooded with warnings about the reversing light faults (shorts).

You can't disable reversing lights in the BSI using Diagbox - it's not an option IIRC.

You will likely have to get some LEDs that have decent load resistors build onto them to prevent bulb out detection (even though it does not flag a warning up to the driver on the display) or the errors being created in the BSI. These reversing bulbs if I remember correctly are the awkward H21W. The issue is because these are 21 Watts, they need a decent load resistance for the circuit and a lot of cheap LED replacements are not up to the job. So you may need to spend a bit more on a decent LED replacement.

I did replace mine with some better bulbs and that seemed to fix the issue - but I don't have the links any longer, sorry.

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fikse
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Re: Extra reversing light C5X7, connect?

Post by fikse »

GiveMeABreak wrote:
11 Mar 2021, 11:10
The reversing light circuit is sensitive to LEDs and will record errors in the BSI and cause erratic behaviour. I replaced my reversing bulbs with brighter LEDs on my X7 for the same reason, but got notified by drivers on occasion that they were flashing! Also, when looking at the BSI fault logs it was flooded with warnings about the reversing light faults (shorts).

You can't disable reversing lights in the BSI using Diagbox - it's not an option IIRC.

You will likely have to get some LEDs that have decent load resistors build onto them to prevent bulb out detection (even though it does not flag a warning up to the driver on the display) or the errors being created in the BSI. These reversing bulbs if I remember correctly are the awkward H21W. The issue is because these are 21 Watts, they need a decent load resistance for the circuit and a lot of cheap LED replacements are not up to the job. So you may need to spend a bit more on a decent LED replacement.

I did replace mine with some better bulbs and that seemed to fix the issue - but I don't have the links any longer, sorry.
Well, Im not into other bulbs, as the lens layout is just to weak. Im into a separate light, close to the tow hook, as on picture. I will try to see what happens when I connect it to the reverse wire for the tow bar. If not try a simple relay with signal from the tow bar electrics or one of the reverse bulbs...
BTW there is an option in Diagbox 9.68 to disable reverse light, either at right or left. Not tried the result of it though..

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Re: Extra reversing light C5X7, connect?

Post by GiveMeABreak »

Never seen that before, interesting - I would only of expected to see that option possibly for vehicles that have a single rear fog light on one side and a single reversing light on the other side perhaps, but I've never seen it on an X7 as an option in the BSI.

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fikse
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Re: Extra reversing light C5X7, connect?

Post by fikse »

I will try it later, to disable one bulb. Try to find all the gremlins that follows 😅
Naah, about the reverse light I think I'll stick to a good old fashion relay and signal from one of the OE bulbs.
About power, is the 12 power outlet at right side the best choice? AFAIK that outlet is permanent and even outside the economy module, and that's maybe not the most desirable for a reverse light. Some of the wires at left side should be 12V steady at ACC and have 1Amp to lend....?

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Re: Extra reversing light C5X7, connect?

Post by GiveMeABreak »

Ok, so I've just checked the latest BSI configuration for the X7 and although there are these options:

Presence of a left reversing lamp
Presence of a right reversing lamp

The notes define these as mandatory to ALWAYS be set to YES on this vehicle. As I suspected the option is used for other vehicles that have one reversing and one fog light - and the C5 X7 always had both reversing lights fitted. So I'm not sure what will happen if you disable one of these.

As for the rear 12V supply, I can't say for sure whether this will be switched off after 30-40 minutes - I know the front one will though.