Hi, as part of sorting my rear bumper I have acquired 2nd hand bumper with fitted revrsing sensors, loom & ecu. Could anyone give me a bit of guidance on fiting wiring etc for reversing sensors please? Thanks … John.
Usually just a body ground and a connection to the reverse light live feed.
Also the part number on ecu is C841-V7-288A
That picture is complete and only missing the transducers, the four bits that live in the bumper. Those blobs on the ends of the leads plug into the transducers.
The blue wire is a test/calibration loop.
. Park the car with rear bumper 50cm from a wall.
. Check the blue wire loop is connected to itself, switch on the ignition but not the engine, select reverse and wait for between 10 and 100 seconds while it self calibrates “BEEEEEEE…P”.
. Switch off.
. Open the loop again and tape the ends to protect them from shorting to anything.
I soldered my + and - onto the tangs at the back of the reverse-light socket, no wires needed cutting etc.
See my installation
Yeah the 4 transducers are on the bumper …
Maybe fitting the parking sensors will prevent me doing what I did to need replacing the bumper!
Does it matter which way round you hook up to the reversing light? Also, seeing as sensors were on an MX5, do I need to calibrate (most probably will anyway…)?
The light bulb itself, no, but wires from it to the reversing sensor control box must be correct polarity + → + and - → -, unless you want it to take up smoking.
All fitted and working well. I used a rear earthing point for ground wire & used the red/yellow wire of reverse light connection to tap in to for red power wire. Pretty much same routing & location of control box as you did…
Only one embarrassing moment! When I checked that sensors were working they were beeping, so I thought something was wrong …
A single beep as you select reverse is normal. Nothing to worry about.
Sort of what I thought, thanks for confirming that…
That looks good.
The other test is to walk close past them and check that each one of them is functioning individually.
Yep … did that all 4 working 
No guarantee!
You might be able to slip a phone up there from underneath between bumper and body to take pictures in the likely places.
My 2008 NC1 Niseko did not have them, nor did my 2014 NC3.75 25AE have them. But some years in between do and you might be lucky…
Here’s how I managed with the 25AE.
