[MrSweet1991]

Hi Peeps,

So please bare with me as I don't have many pictures as it was late by the time I finished but..

I purchased a reverse camera off Amazon for just 18 spondoolies which I thought was a bargain, I have an Xtrons PE9890BIPL with a Rear Video in phono so everything is good to go.

Now, from what Iver heard about these cameras many people have issues with black screens or lines occurring when the reverse camera coming on which is due to the fact we tap into the reverse light and Ground wire to pull 12v which doesn't actually provide 12v when the engine is running, it's more like 11.7 hence the issues (from what I've read anyway)

So rather than mess around I purchased a 4 pin 12v relay with a 30a fuse to ensure I can supply 12v directly from the battery.

So, my camera works but it appears a little grainy and maybe a little flicker but I don't think many people would notice as its minor. So here's how I wired the camera.

I cut the Brown wire and the black and blue striped wire from the rear inside light (attached to boot) the brown wire is ground and the blue and black striped is the reverse light wire. With the reverse light cut I soldered it back together with one extra piece of wire that goes to the relay

The ground reverse wire was soldered with an extra piece of wire to go to the relay and these two wires made the "switch" section of the relay.

I then connected a wire to my positive battery terminal and placed this to the fused section of the relay which will supply the 12v when the relay is activated via the reverse lights ground and reverse light wire.

The 4th and final wire on the relay is the camera itself

So, on the xtrons side I connected the yellow phono into the "rear video in" but on the rear cameras yellow phono wire there's also a little red wire.. I have no. Idea why this is there but the camera comes in without that being connected.

Now despite the camera coming straight on it looks grainy and perhaps a slight flicker, I checked the wiring and found I forgot to solder the reverse cameras ground wire to the reverse lights ground so this wasn't connected. I did hold the ground wire of the reverse camera onto the reverse lights ground but it actually seemed to cause the camera to flicker which was strange.

So any ideas, sorry about the long description its the relay wiring that I find hard to explain.

Here's a picture of the relay which I've numbered

View post on imgur.com

Number 1 of relay - Wired to battery terminal (positive)
Number 2 of relay - connected to reverse light ground
Number 3 of relay - connected the reverse light
Number 4 of relay - connected the reverse camera positive wire

Theory is, number 2 and 3 of relay which is reverse light and Ground will trigger the relay to let number 1 of relay to supply 12v power from battery to number 4 of relay which is the reverse camera.

[Andystobbs]

Try a ground further away from the reverse light.

[MrSweet1991]

Originally Posted by Andystobbs

Try a ground further away from the reverse light.

Thanks mate, do you think I should add another wire from the relay down to the chassis ground that's located by the battery or is there something closer?

And any thoughts on the reverse cameras ground? I didn't mean to but its actually not connected but still works.. The ground connected to the relay is the ground wire from the reverse light.

It doesn't seem to be running too bad to be honest I'll have to check better tomorrow.

https://youtu.be/Rq22zzZ52XA

[Andystobbs]

You may be getting away with the camera grounding through the video lead and subsequently the radio itself. The phono lead is infact two wires inside.

If the camera has night vision you may find it works better when grounded by a dedicated wire.

The reverse light is actually pulsing on and off rapidly, which is why the voltage appears to be lower than 12v, a standard multimeter will display an average voltage reading in this case.

If your connection is very close to the rapidly switching reverse light bulb it may be picking up electrical interference from this. A ground on the bootlid itself would be worth a try before pulling a wire back through to the chassis ground by the battery.

The red wire in the phono lead is a third wire in the case of your phono lead intended as an easy option to get a reverse signal to the radio to command it to display the image when in reverse gear.
I'm guessing you've done this part with a can decoder?

[Loki45]

I have a 2009 BMW 328i automatic. I am trying to install the back up camera. I have a relay. I wonder which wire color to tap into the reverse light. I currently tapped into a black/blue wire. But it seems to be a brake light. So if I reverse and release the brake, the camera shut off.

Attached is my wire picture



https://imgur.com/gallery/u5klm4B




Thanks in advance,

[Loki45]

Nevermind. I figured it out. I tapped into a break light which is next battery.

[MrSweet1991]

Originally Posted by Loki45

Nevermind. I figured it out. I tapped into a break light which is next battery.

If you have it, ISTA+ has wiring diagrams, it's how I confirmed mine. Mines been running great with the relay

[billabong02]

Originally Posted by Loki45

Nevermind. I figured it out. I tapped into a break light which is next battery.

Hi,

I'm trying to do something similar. When you tapped into the brake light, was this to establish a ground connection?

Is it the brown wire that's the ground?

Thanks

[Loki45]

Originally Posted by billabong02

Hi,

I'm trying to do something similar. When you tapped into the brake light, was this to establish a ground connection?

Is it the brown wire that's the ground?

Thanks

No I was trying to use brake light provide power to the relay. Brown line is ground correct.

[Mvy]

Sorry to revive a dead post. E93 6mt. Trying to use mr12volt to add a back up camera. It has both a rear camera trigger wire and dedicated 12v power line in addition to the rca plug/ground for the video. I have the same isssue, but my harness has 2 black and blue wires (see attached) at position 6 and 3. Does this relay work on a 6mt or just auto transmissions? I tried but may have wired it wrong. I also had to run a direct line from mr12v to the camera for stable power, but never figured out the right tail light wire to connect to. For power I figure it may be easier to connect to the battery as its closer than running to the glove box (though the wire is in now).2.pdf

[Mvy]

Originally Posted by Loki45

Nevermind. I figured it out. I tapped into a break light which is next battery.

Next battery as in the purple and yellow one? what color wire did you end up tapping that worked?

[pmorg4]

You can tap directly into the reversing light in the boot lid, black/violet on the left or black/blue on the right. The only issue is that when the engine is running the power will be very quickly switched on and off (PWM) to keep the voltage to the bulb steady, which may cause problems with the camera. This can be solved by coding out the PWM on the reversing lights in the FRM using NCS expert.

[Mvy]

Originally Posted by pmorg4

You can tap directly into the reversing light in the boot lid, black/violet on the left or black/blue on the right. The only issue is that when the engine is running the power will be very quickly switched on and off (PWM) to keep the voltage to the bulb steady, which may cause problems with the camera. This can be solved by coding out the PWM on the reversing lights in the FRM using NCS expert.

Thank you. That may be the issue for me. I have bimmercode so will dig around in there and see if I can code out the PWM.

[Mvy]

Final post, turns out no coding necessary. Im running off mr12v not the cars canbus so not even involved. I ran a direct power line off the mr12v. Selecting the 4th wire for the trigger (not 3rd as most have called out) off tail light, one of the two black and blue for the black trigger wire was the problem. I now have a rear view cam, no relay needed!! 2008 e93 m3.

[askme]

Originally Posted by Mvy

Final post, turns out no coding necessary. Im running off mr12v not the cars canbus so not even involved. I ran a direct power line off the mr12v. Selecting the 4th wire for the trigger (not 3rd as most have called out) off tail light, one of the two black and blue for the black trigger wire was the problem. I now have a rear view cam, no relay needed!! 2008 e93 m3.

Any tips on routing the wires on an e93? I see others routing through the existing rubber boot, but the e93 seems to have a lot more, and a lot tighter routing to say away from the top mechanism.

I was considering just wrapping around the existing harness and strapping it down with electrical tape, etc.

[Mvy]

I tore out my first cameras wireing after thinking I was done and operating the top for the first time, so I understand your concerns. I did follow the rubber boot and the other wires down the top frame towards the brakelight. The pivot at the brakelight is the area to leave some slack, but not enough to get caught up in the works. Use zip ties, but leave them loose until you operate the top a few times, carefully watching where you may need to leave slack or tighten. It took me about 30 mins but no problems since. Black electric tape at the end to hide is a good idea. I did that in some spots. You can even use it to create a more durable cord in the weak places. My full write up is on m3 post here. https://www.m3post.com/forums/showpo...postcount=1418