Had the same Kenwood head unit and back up cam since 2018. Well, back in late 2018 after the head unit/cam were installed months prior, I had to replace the starter and battery. Once I replaced them, I would get wavy lines on the display of the back up cam, which were never there before. The odd thing, is if the car is not running the picture is perfectly clear, its not til the car is actually running that I'm getting noise/interference. Power and ground were hooked directly to the battery in the trunk, with the turn on signal coming from the reverse fuse on the passenger side footwell fusebox. I've moved the ground off the battery to inside the rear bumper where there is a factory ground, but this didn't remedy the situation. Anyway, Im replacing the headunit with a newer Kenwood, just curious if the audio gurus in here would have any ideas on how to eliminate the interference. I did try one of those RCA ground loop isolators and it didn't change anything.

 

Try changing your trigger signal.

 

Any suggestion to what? The trigger is specific to reverse only, so I don't know what else to use. And if it's from the same fuse block, what would be the difference? But I appreciate the advise!

 

The radio adapter harness should have a reverse output. If it's the pac adapter, it's a purple and white wire. Which adapter do you have?

 

on my new head unit that's not installed, I have a PAC RP5-GM11 adaptor attached, that has a solid purple wire thats not attached to anything. Now coming out of the Kenwood head unit is a purple/white wire labeled "reverse" on it. The crutchfield instructions say to connect those two wires together, or im an idiot.

 

I mispoke, the switched 12v power is tapped into the reverse fuse in the fuse box, the trigger on the current head unit is from the reverse wire on the head unit from what I can remember

 

Ok. Then switch the 12v source to the ignition wire (ACC)at the radio.

 

much appreciated, Ill try that. Curious, why do you think the 12v source from the reverse fuse is causing the interference? And why did it happen once I changed the battery/starter?

 

It’s possible that the circuit is getting interference from other circuits in the fuse box, however changing the battery/starter could have caused a little glitch in the electronics that is known to happen in these cars. I suggest disconnecting the battery for a few minutes, then hooking it back up and see what that does (don’t forget to reindex your windows, and you’ll probably have to reset your favorites on your stereo). If that doesn’t do it, then come off another source for you backup signal, The RP5-GM11 should be wired as follows: The Purple/White wire is the reverse signal trigger wire and should be wired to the corresponding wire on the head unit, this will trigger the head unit to display the camera when the car is put in reverse. The Blue/White wire is the amp signal wire, this should be connected to the corresponding wire on the head unit, this wire sends a signal to the cars amp, to turn on when the stereo is powered up. The Blue wire is not used.

Vince C5 mentioned connecting to the Red Acc wire, if you do this it should be the cameras 12V+ wire connected to this, this will power that camera all the time when the car is running, but you’ll still need to trigger wire (Purple/White) attached as mentioned to trigger the head unit to display the camera automatically when the car’s in reverse. The advantage of connecting the cameras 12V+ to the Red Acc wire, is that you can view the camera anytime you want just by turning it on when driving down the road which is handy if you’re pulling a trailer or something, which is probably something you would’t need to do on a Vette, but I have it wired this way on my truck which is handy when pulling my boat. If that’s a feature you’t not concerned about then I suggest you just connect the cameras 12V+ to the Purple/White wire in addition to connecting it to corresponding trigger wire on the head unit, this’ll only power the camera when to car’s put in reverse (as it’s a 12V+ signal only when the car’s in reverse) and will also trigger the head unit to display the camera at the same time.

Another potential issue is that you don’t have a good solid connection on the cameras video out and the head units video in RCA connections, you might try unplugging them, then plugging them back in.

Hope all this makes since, if not let me know.

 

thanks guys, really appreciate the insight. Madsonp, I would like that ability to have the camera powered at all times. So I purchased the prewired harness from crutchfield. In the picture I have attached, the red wire coming out of the back of the head unit (the red wire on my index finger) thats the one I should use? Not sure what its connected too as it is.

 

Yes connecting the Red 12V+ wire of the camera to the 12V+ Acc wire between the interface and head unit will keep the camera always powered on when the car’s running, so you want to keep it wired as is in your picture and just tap in your cameras 12V+ wire into it. Which head unit are you running ?

 

perfect, its a Kenwood DMX709S