Help needed with reversing sensors please

[Snertsmate]

Hi all,
Newbie here so please be gentle.
I am looking to fit a set of reversing sensors on a car.
In the old days I would just connect a relay into the reversing light wiring to switch the power to the sensors.
Now with CAN and suchlike I understand that this can cause problems.
I am looking for some sort of non invasive sensor that I can use to detect a current in the wire and operate a switch to control the reversing sensors power supply.
I am looking for something cheap and off the shelf if possible but could build a simple circuit if someone can help me with a circuit diagram and not too technical instruction, I can be trusted with a soldering iron.
Thank you in advance
Snerts

 

[Bluejets]

Get a bit of enamelled copper wire, maybe about 18 gage. Wind about a dozen turns around a glass reed switch( may need more depending on bulb current) cut into the reverse cable and solder the winding part in series. Use reed switch via a transistor or mosfet to turn on the new device. I'd include a diagram but on the mobile presently.

 

[Tha fios agaibh]

Interesting idea Bluejets, but it's also likely the sensor current will not draw enough current to trigger a fault.
It's common to add back up cameras to reverse light circuit and I haven't heard of any can-bus problems.

 

[Bluejets]

Interesting idea Bluejets, but it's also likely the sensor current will not draw enough current to trigger a fault.
It's common to add back up cameras to reverse light circuit and I haven't heard of any can-bus problems.

Sorry, no idea what you mean about sensor current and also "fault".
Reed activation is from magnetic field set up from reversing lamp current.

 

[Snertsmate]

Thanks guys but hardly non invasive, its a new car and I don't want to invalidate any warranty, my old man would do his fruit.
Any other ideas?

 

[Tha fios agaibh]

Sorry, no idea what you mean about sensor current and also "fault".
Reed activation is from magnetic field set up from reversing lamp current.

Sensor current: Meaning the additional load the backup sensors will add to the reverse lamp circuit.
Fault: Meaning the circuit error that will be generated by the cars control module (ecm) by adding too much of a load to the reverse lamps.

 

[Tha fios agaibh]

Thanks guys but hardly non invasive, its a new car and I don't want to invalidate any warranty, my old man would do his fruit.
Any other ideas?

Your technically voiding your warranty by adding the sensors, but most dealerships are reasonable when it comes to added accessories like this provided your not a total hack.
You could use piggyback splices that are not too invasive to see if it works. Then if you chicken out, you can always remove it and will only have two slight piercings of the wires.
Make sure to get permission from your old man before making Swiss cheese out of your bumper.

 

[Bluejets]

Sensor current: Meaning the additional load the backup sensors will add to the reverse lamp circuit.
Fault: Meaning the circuit error that will be generated by the cars control module (ecm) by adding too much of a load to the reverse lamps.

No need to do either.

 

[Bluejets]

Could find a hall effect split clamp sensor for dc that would monitor reverse lamp current or use an ldr to monitor the lamp but as mentioned, any changes will be "invasive" to some extent. USS Enterprise sensors not available just yet.

 

[Tha fios agaibh]

No need to do either.

It was a clarification not a proposal.

 

[Tha fios agaibh]

Why come up with a work around when there likely isn't a problem?
Just tap into reverse light wire like most after market sensors and cameras suggest in their instructions.