Reverse Light Check

[jaynana]

Hi,

is there a way to switch off the light check on the reverse lights please?

I have the ever famous reverse camera mod. it works but the light check is driving the relay nuts!

thanks

jay

[marlin758]

Hi

Yes there is - but a dealer can do it  or it may well be worth getting BMWScan 1.4 off ebay  ( approx £30 or less and you can program it yourself.

Or if you are lucky another member with BMWScan who lives near you will offer to do it for you 

[Sanj]

[quote="jaynana"]
I have the ever famous reverse camera mod. it works but the light check is driving the relay nuts!
[/quote]

You shouldn't be getting any issues with the relay and the light check. I don't.

[jaynana]

marlin758, i have the scanner, thanks. it actually has an option to switch off cold and/or hot checks on each light (see the Light Coding screen here). that didn't work, which makes me think something on the lines of what Sanj is saying.

Sanj, the symptom is as below:
Scenario 1. engine not running, key in position 2, put gear gear into reverse-> relay engages, camera works perfectly.

Scenario 2. engine running (key in position 2), put gear into reverse-> relay starts making a continuous pulsating 'TRRRRRR' noise! audibly it must be like 10htz or so.. the camera still works because the frequency is enough to flip the video module to show the camera feed. but occasionally the screen flickers.

the bulbs have a hot check and a cold check. so i assumed this to be the hot check.

in fact i did a further test: while in Scenario 2 above, i touched a direct +12v onto the reverse light pin on the relay (through a 5A fuse just in case). and sure enough the relay stops pulsating and sure enough, a 'Check Reverse Lights' comes up when the key is later turned off. this is why i assumed it must be the hot check.

Scenario 2 is difficult to test alone: the engine running, gear in reverse, and I have to be standing behind the car meddling inside the boot!! literally asking the car to run me over!!  :'(



ps
also my relay is next to the video module, so it can only be observed/heard with the the spare and compressor off, because otherwise the sound is muffled and cannot hear it from inside the car.

[marlin758]

Hi Jaynana

Have a look at this .

http://www.xoutpost.com/bmw-sav-forums/ ... issue.html


Supposedly cures it using an extra relay .

Regards

Terry

[jaynana]

thanks marlin758, that 'noise' being discussed there is exactly what i'm after, although the symptom is somewhat different (i don't have running lines going across the display etc i have a flicker on the screen, once in a few seconds)

i'm inclined to try a different route, like a capacitor to absorb the noise and hold the relay down.. if i can't switch the light check off through software that is, plus also not sure how that will impact the light check...

btw, i also did that manual override they're discussing there - wired to a switch in the front ashtray. i have a ERDE 122 teeny weeny trailer which is invisible in the rear or side view mirrors when hooked up. manually switching on the reverse camera gives me a full view of it while driving! must post an update there..  :-[

[jaynana]

guys, figured this out and came up with a solution as well, thanks terry for the link that made it possible!

basically its not the hot or cold light check that's impacting the relay, it is in fact an additional  PWM that the LCM sends to modulate the brightness whilst the voltage fluctuates due to the alternator etc.

the solution i did in a nutshell was to switch the activation of the relay from the reverse light to the PDC.

i will add more info to the Reverse Cam Install thread so that all the information is in one place, to help anybody else who may come across this.. plus i believe what i have now is a better install than the

cheers

j