Rx400h black lines flickering on reversing camera screen

[Richard 86]

Hello, a couple of days ago my 06 RX400H screen developed an intermittent fault where it would have horizontal lines only when viewing the reversing camera.

Some times it's fine, sometimes there's two or three black lines, sometimes there's about 20 lines and it's impossible to use.

I suspect the fault is in the dash, as sometimes (not always) it works fine if you give the dash near the screen a good whack.

 

I pulled the radio and screen out today and couldn't find any loose connections or anything.

 

Oddly there is one plug in the radio that has two wires. If this plug is not connected neither the reversing camera, maps nor the climate control will work.

 

This means it could either be the radio or the screen computer that are at fault.

I suspect the processing for the camera happens in the radio and it send the image to the screen, but this is a guess.

I really don't want to play the trial and error game as even second hand, each item involved is £150+. So if I swap the screen, radio and camera and still no luck I'm £450 down.

 

So, any suggestions how to narrow down the issue further?

[PCM]

Condensation/water 'in' the wiring at the back?

[scudney]

Also do bear in mind that like everything else,these things don't last forever,its now getting on near 15 years so could equally be age related 

[ColinBarber]

Your problem almost certainly lies in the boot. Either camera, camera ECU or wiring in-between - likely moisture related.

The camera puts out a composite NTSC signal into the camera ECU. This is converted to RGB, overlaid with graphics and the output sent to the screen. The wiring diagrams imply the Nav system output goes into the camera ECU then onto the screen via the same RGB cable, therefore if there is a problem with the camera ECU output or the screen you would be getting the same issue when displaying the nav screen.

[Richard 86]

@ColinBarber thanks for the useful info.

After finding nothing obvious in the dash I removed the camera. I wasn't expecting to find anything as the issue seemed to disappear after hitting the dash so I was convinced the problem was upfront.

Anyway, the camera had aluminium oxide all over it.

I pulled it apart (had to drill out some of the screws) and noticed that the two circuit boards inside the camera came apart really easily. Almost fell apart. 

They joint with a electrical connection thing.

On reassembly the two boards clipped together much more positively. Aluminium oxide doesn't conduct electricity, but maybe it forced some of the components apart? Not sure.

Anyway, so far it's worked perfectly since and not a penny spent. Always happy with that type of result.

It's been a week now so pretty confident it's sorted.

 

Thanks again.