installing reverse cam on chinese double din unit. help needed.

[chapel gate]

woke up christmas morning to find a chinese double din head unit with sat nav reverse cam etc at the bottom of the bed.

fitted the head unit and everything works fine. got on the reverse cam today. i wanted the camera to come on in reverse and when the av screen is selected so i have the cam live connected to the acc connection, earthed at the number plate light earth. i also have a wire going from the reverse light positive to the reverse signal wire coming off the head unit. so when i put the vehicle in reverse the camera comes on as it should, but when i select the av screen it says there is no signal, interestingly if i plug the av lead into the video input socket on the back of the head unit instead of the reverse socket i get a picture, but then it wont work when put in reverse! stating no signal!

its cold and dark and now im out of ideas..

 

[Chris]

Only thing that springs immediately to mind would be the earth at the number plate light.

 

[chapel gate]

The side cutters will soon tell me if thats the issue chris.. everything is soldered and heat wrapped. Will get on that first thing with a fresh head.

 

[Steve H]

Hi. I thought that the head unit would have a dedicated input from the camera to automatically switch the screen to view what the camera is seeing. I have the meos one and there is a yellow input for the camera to plug into. Is there not a plug marked rev cam on the loom? On the camera lead is there a red wire as well as the input for the camera signal? Most cameras take the reverse light feed at the camera end and send this to the head unit switching the screen over automatically using the red or coloured wire.

 

[chapel gate]

The camera works perfect when i select reverse. The yellow av lead is plugged into the back of the head unit. Ive powered the camara from the acc wire so it allways has power when the ignition is turned on. By doing this i should be able to switch to the camera even when reverse is not selected. Im just getting "no signal" though when i switch to av manually on the head unit. Works great when reverse is selected though...

 

[StarCruiser]

CG, selecting AV is selecting the AV or secondary input used for DVD players, tv players or indeed a front mounted camera. What you have done is to wire it all correctly. The ONLY way to do what you want is to fit a two way switch to FEED the red wire that runs from front to back at the point it connects to the rear camera sense wire at the back of the head unit not fed from the rear directly. The Earth at the back will be fine. You may need to use a thicker wire but we'll assume the supplied one is ok. Wire this wire to the common of the two way switch. Then one side of the two way needs to be connected to the reverse signal which maybe easiest via a wire from the rear. The other side of the two way switch needs to be connected to + via the ACC. That way in one position the camera works on reverse signal and on the other it will be switched on and running and will switch the screen input over to camera.

[emoji6]
Have fun[emoji4]

 

[chapel gate]

Cheers sc. There are separate inputs for forward cam,dvd,tv etc though. Do you think the unit wont support what i want it to do? A lot of people seem to of done this.

 

[StarCruiser]

Like this- AV yellow camera connection omitted for clarity but goes from camera to 'rear camera' phono (RCA) plug on back of head unit.

The two way switch could be a relay with the obvious added wiring.

 

[StarCruiser]

Cheers sc. There are separate inputs for forward cam,dvd,tv etc though. Do you think the unit wont support what i want it to do? A lot of people seem to of done this.

Pretty sure it will do it, all you are doing is selecting via an internal relay in the head unit rather than a button on the front.

 

[chapel gate]

Thanks for your help sc. I didnt want an external switch, so i drank even more beer and thought harder as is often the case the solution was simple, i got a av splitter and connected the other connector to another av input in the back of the unit. Bingo works a treat. I think these units are the way forward once software and quality issues are sorted out.

 

[StarCruiser]

Glad you sorted it CG. [emoji4]