View Full Version : Reversing camera wiring

01-25-2014, 09:09 PM
I have just had a reversing camera fitted to my 2010 sprinter, the guy took the power from the interior light and cut into the reversing light wire as well,
The problem I am left with is now it has effected the radio reception, does anybody know what I have to do to over come this problem.

Thanks all

01-25-2014, 09:16 PM
...does anybody know what I have to do to over come this problem.

Unhook the camera from the lighting and reverse wires.

01-25-2014, 09:48 PM
Unhook the camera from the lighting and reverse wires.

And wire it in where?

Walter Clark
01-26-2014, 03:28 AM
Is this a camera and monitor? Is the monitor powered by the power at the dome light and the camera by the reverse light?

I am at a loss to see how the camera hookup (other than being a little half assed) would mess up your radio reception unless the installer some how disconnected or tapped into the antenna preamp power instead of the dome light to power the monitor.

First step would be to disconnect the camera and monitor and see if the radio works normally again.

01-26-2014, 09:10 AM
It is a camera and monitor, the monitor is powered by the dome light and the camera by the reverse light. But all the wires sit about 8 inches directly below the antenna, it does seem to make a difference when you move the wires away. But puzzled why this should interfere with the radio.

Walter Clark
01-26-2014, 02:03 PM
It really shouldnt, but obviously it is. I will assume the power wire to the antenna preamp was not the one tapped to provide power to the camera - you should check to be sure of this.

The interference might be radiated from the monitor itself or coming from its power line. You can check this by moving the monitor away from the antenna preamp. You already suggested moving the power wire changed things a bit. Radiated energy follows the inverse square law so doubling its distance from the antenna will reduce the energy seen by the antenna by the square root of the original.

The interference may be radiated because of a poor power ground to the camera or the monitor. I assume the camera power and ground are from one of the tail light assemblies. Where is the monitor ground?

Sometimes devices with a lot of digital stuff going on inside, like the monitor feed noise back out the power line. One of those big ferrite put on the power wire at the monitor can reduce this a lot and is probably the fastest and easiest thing to try first. For most people the quickest place to find one is Radio Shack - like this http://www.radioshack.com/product/index.jsp?productId=3012599&locale=en_US The power wire passes through it then once around the outside and back thru it again like a loop. These particular models open up so you dont even have to disconnect the power wire.

I would re-do the monitor power and ground...even if the ferrite seems to take care of the problem. Tapping wires like that for power is an ugly way to do anything and if you develop a problem with lighting or anything else that shares the interior lights fuse, you may have problems getting MB service (or anyone else) to touch it. I suggest that you run the monitor power and ground to an unused, switched, fused location, either on the fuse box at the bottom of the drivers a pillar or to a location on the fusebox under the drivers seat (preferred for any add-on) and run the power ground to a vehicle chassis point nearby the selected fusebox. You will probably find a small stud welded to the chassis with a nut in either location that is either unused or has room for another ring terminal. See the next paragraph regarding tapping into wires. If the interior light power wire and/or a nearby ground wire were tapped using a common insulation penetrating quick tap, the wire itself may have been damaged. The tap should come off and the wire inspected. Then either insulated if undamaged or repaired if damaged. You can tell if it was damaged by bending the wire where the insulation was cut into. If you see cut thru conductors, the wire was damaged and it should be stripped back rejoined and solder spliced then insulated.

The camera power and ground going to one of the tail lights is also inelegant but it is very common. Since a backup camera draws around a tenth or less the power as a backup light bulb from the wire powering the bulb, so long as there is no fault in the camera or wiring, the vehicle systems should in theory never notice. One problem with common taps however is the use of insulation penetrating taps. If correctly made and sized they will not damage the wire that is tapped into, however I have seen many cases where the tap was incorrect and the installation of it weakened the wire by cutting a number of strands and it eventually caused the wire to break at that point. Of course this always happens long after the installer has disappeared. The only safe and reliable tap is one where a bit of the wire to be tapped has a bit of insulation striped back, the leach wire is wrapped and soldered onto it and the joint is well insulated with high quality self-vulcanizing rubber tapes like 3M rubber splicing tape. This tape doesnt come off, seals out moisture and supports the wire at the ends of the solder joint to reduce metal fatigue.

The power half of this tap should be in-line fused with a 1A fast blow near the tap-splice to protect the vehicle from a fault.

01-26-2014, 04:39 PM
Thanks Walter for the responds, there are three wires, 1 that joins the reversing light 1 that has been joined to the positive feed to the interior light and 1 that has been joined to the negative of the interior light.
I will remove the wiring and see if it changes, if it does I will know for sure then, but like you say it's better to take it from its own fuse under the drivers seat so that's what I will do.
I will let you know how I get on.