OEM Rear-View Camera to Aftermarket Head Unit
09-12-2018, 10:09 AM
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GL450
OEM Rear-View Camera to Aftermarket Head Unit
I just replaced the Comand head unit (non-Harmon Kardon) on my 2012 GL450 with an aftermarket unit. Remarkably, everything is working well except for the back-up camera.
I'm using the OEM camera as I didn't want to take apart the tailgate. This is how I connected the new head unit to the camera:
-- Camera video input to vehicle's green fakra behind the dashboard.
-- Reverse trigger wire to vehicle's reverse light wire on the passenger side (white with black stripe).
When I attempt to turn on the camera by pressing the button on the head unit (without shifting into reverse) I get a black screen with just the guidelines (i.e. no video signal from the camera)
However, when I shift into Reverse, I do the get rear view video. Based on this behavior, it seems that the camera is powered when the vehicle is shifted into Reverse. I assume:
-- Pressing the camera button switches the head unit to camera mode but I get the black screen because the camera itself isn't powered
-- Shifting into Reverse also switches the head unit to camera mode but I do get video because the camera is now turned on when in Reverse
Here's the problem. When I'm in Reverse, every so often the head unit goes back and forth between rear video and the screen that I was on before shifting. I assumed this is caused by power fluctuations coming from the white/black reverse wire. So, I installed this filter. However, although the camera still works I also get a reverse light warning on the dash and it won't go away. So, I uninstalled the filter. I then checked the voltage coming from the reverse wire that I tapped into. When in Park it's 14.5 volts and when in Reverse it's 12.5 volts. Now I'm at a loss as what to try next.
Does anyone have any ideas as to:
--What I should try next to provide steady 12 volts to the headunit when in Reverse (without causing a reverse light warning to appear)?
--Where the power is physically connected to the back-up camera itself? I'd love to power it from the headunit rather than the reverse light.
Thanks,
Peter
I'm using the OEM camera as I didn't want to take apart the tailgate. This is how I connected the new head unit to the camera:
-- Camera video input to vehicle's green fakra behind the dashboard.
-- Reverse trigger wire to vehicle's reverse light wire on the passenger side (white with black stripe).
When I attempt to turn on the camera by pressing the button on the head unit (without shifting into reverse) I get a black screen with just the guidelines (i.e. no video signal from the camera)
However, when I shift into Reverse, I do the get rear view video. Based on this behavior, it seems that the camera is powered when the vehicle is shifted into Reverse. I assume:
-- Pressing the camera button switches the head unit to camera mode but I get the black screen because the camera itself isn't powered
-- Shifting into Reverse also switches the head unit to camera mode but I do get video because the camera is now turned on when in Reverse
Here's the problem. When I'm in Reverse, every so often the head unit goes back and forth between rear video and the screen that I was on before shifting. I assumed this is caused by power fluctuations coming from the white/black reverse wire. So, I installed this filter. However, although the camera still works I also get a reverse light warning on the dash and it won't go away. So, I uninstalled the filter. I then checked the voltage coming from the reverse wire that I tapped into. When in Park it's 14.5 volts and when in Reverse it's 12.5 volts. Now I'm at a loss as what to try next.
Does anyone have any ideas as to:
--What I should try next to provide steady 12 volts to the headunit when in Reverse (without causing a reverse light warning to appear)?
--Where the power is physically connected to the back-up camera itself? I'd love to power it from the headunit rather than the reverse light.
Thanks,
Peter
