Mirror reversing-camera doesn’t activate when reverse selected

[LBird80]

Hi all.
I’m sure I’ve read the fix for this on here somewhere before but I just can’t find it again now.
My van has a mirror type reverse camera. It started to only come on intermittently when reverse is selected. I’d say 95% of the time it won’t come on but the lights on the mirror start to flicker. It’s clearly trying to come on.
However if I push the button on the mirror to turn it on manually it works perfectly.

Can anyone here help and advise why it’s doing this and what the fix is please.

Clearly pushing the button is such an inconvenience for me.

Thanks in advance.

 

[JimmyMac74]

Do you have aftermarket rear lights?

 

[LBird80]

Do you have aftermarket rear lights?

No mate. Standard ones

 

[LBird80]

It’s like it’s not quite getting enough power if that makes sense.
Just can’t understand why it works fine when I turn it on manually.

@Dav-Tec or @Absolut5 do you know what it might be at all?

 

[roadtripper]

Sounds like a bad connection, check the soundness of the wiring and look for any corrosion or wear.

 

[LBird80]

Sounds like a bad connection, check the soundness of the wiring and look for any corrosion or wear.

Do you think it’s likely to be where the camera takes the feed from the reverse light that might be dodgy given it works ok when I power it up manually?

 

[david173]

Assuming the camera has its own power feed , judging by the fact you can manually turn it own I would say it does, then it sounds like the issue is the reverse feed isn't triggering the power to come on correctly as @roadtripper suggested a bad connection potentially at the relay, can you find the relay switch at all and then test it on there?

 

[roadtripper]

They are likely totally separate signals.

If the camera switches over manually it means the core functionality is working.

It could be an internal fault that is causing it not to detect the voltage from the reverse lights (assuming that's how you are doing it not via canbus detection) but first check the external wiring.

 

[david173]

The signal to the reverse light is switched by the BCM. It's not a clean signal and some cameras will belly ache with it. In this instance the reverse light signal is used to trigger a relay to supply a clean 12v supply the the reverse camera.

How is your camera wired in?
have you used a clean 12v feed switched by a relay as Deaky outlines above from another thread, or are you trying to take power from the reverse light feed?

 

[LBird80]

How is your camera wired in?
have you used a clean 12v feed switched by a relay as Deaky outlines above from another thread, or are you trying to take power from the reverse light feed?

Ah. This is the one I couldn’t find.
I’m not sure how it’s wired. It was fitted prior to me purchasing the van.
I’ll try and take a look the weekend.

 

[Absolut5]

Hi all.
I’m sure I’ve read the fix for this on here somewhere before but I just can’t find it again now.
My van has a mirror type reverse camera. It started to only come on intermittently when reverse is selected. I’d say 95% of the time it won’t come on but the lights on the mirror start to flicker. It’s clearly trying to come on.
However if I push the button on the mirror to turn it on manually it works perfectly.

Can anyone here help and advise why it’s doing this and what the fix is please.

Clearly pushing the button is such an inconvenience for me.

Thanks in advance.

It’s probably down to where the reverse feed has been taken from, not a clean 12v feed . But without seeing pictures or seeing it in person its hard to diagnose

im sure a relay on the reverse feed will sort it though

 

[LBird80]

It’s probably down to where the reverse feed has been taken from, not a clean 12v feed . But without seeing pictures or seeing it in person its hard to diagnose

im sure a relay on the reverse feed will sort it though

Are they usually wired to the rear lights or do they take the reverse feed from somewhere in the front. Just wondering where to start looking for wonky connections or a missing relay.

 

[david173]

Are they usually wired to the rear lights or do they take the reverse feed from somewhere in the front. Just wondering where to start looking for wonky connections or a missing relay.

assume your a t6 by your pic?

I have mirror reverse cam too like yourself.
best way to wire it in for this type is to have a clean 12v supply from the fuse box, usually from under the centre of the dash, look in there you might see a piggy back fuse.
this goes to a relay which could be anywhere in the front but likely to be behind the dash somewhere near/behind the glove box or side of the dash passenger side. if you engage reverse you might be able to hear the relay 'click' to help find it, although if the relay is not working you might not.
a feed is also taken from the rear reverse light to to relay, the BCM switches this wire to live (to illuminate rear light) this could be from behind the glove box (think its a green/black wire from memory) this is used as the switch/trigger on the the relay ( a relay is just an electronically activated switch) to send the clean 12v feed to the mirror screen when reverse is engaged.

if you find the relay you can check all the connections, it would also be worth checking the earthing for the camera, usually a black wire earthed to the chassis often on a screw in the side of the dash.

not using a new clean 12v feed and relay, and trying to power it from the rear light often wont work as the light supply is BCM controlled and does funny things (beyond my knowledge) so wont give the screen the power it needs.

Thats how mine is wired in anyway, im sure there are other ways of doing it but hopefully that may help

 

[david173]

if you do have a relay, i would check the connections with multi meter . eg when reverse is engaged the you get 12v at the trigger and you are getting 12v on the clean feed. you should also be able to hear it click when the trigger gets power i.e when you select reverse

 

[LBird80]

Amazing. Thank you.
I didn’t get chance to look at it last weekend but last night I did notice that when the ignition is on but engine not started and reverse gear is selected the camera operated fine.
I left it in gear and started the engine and then the camera started having a hissy fit again and wouldn’t come on.

Does this suggest the relay is duff or something else?

 

[david173]

Amazing. Thank you.
I didn’t get chance to look at it last weekend but last night I did notice that when the ignition is on but engine not started and reverse gear is selected the camera operated fine.
I left it in gear and started the engine and then the camera started having a hissy fit again and wouldn’t come on.

Does this suggest the relay is duff or something else?

That one is beyond my knowledge im afraid. Hopefully someone will come along who can advise what the van electrics do differently in each scenario which may give you an indication of where the camera gets its power?

 

[Robert]

Amazing. Thank you.
I didn’t get chance to look at it last weekend but last night I did notice that when the ignition is on but engine not started and reverse gear is selected the camera operated fine.
I left it in gear and started the engine and then the camera started having a hissy fit again and wouldn’t come on.

Does this suggest the relay is duff or something else?

It won't flicker if you disable PWM or use additional relay.

Yes, PWM can be individually switched ON or OFF. To switch OFF PWM for reversing lights Byte 11 bit 4 needs to be deactivated(unticked) in BCM(address 09).

 

[LBird80]

Thanks Robert.
I’ve no idea what PWM is or how to turn off. I only have Carista.