I'm going to be regularly carrying a long kayak on my roof, which needs its overhanging back end tying down.
I've screwed in a towing eye. I'd like to leave this permanently in. But understandably I now get a beeeep all the time I'm reversing. The display shows the obstruction is on the corner, so I think it's only being seen on that one sensor, not the one to its left...
Is there a way of disabling this one sensor? I have the dealer software on a laptop and an interface. I also don't mind doing a bit of electronic trickery if necessary, e.g. fudging a resistor or similar so the computer thinks the sensor is connected when it's not.
The plan is to pull it apart, see how it works then butcher it so it appears to be a sensor but doesn't ever see anything, then reseal it. Then replace the sensor with my modified one, keep the original one safe somewhere.
It looks like it has a 3-pin interface. Does anyone know the pinout? I'm hoping it's a simple analogue level output, but expecting it may be some complicated CANbus thing.
It would be on and off twice a week. It's not for a one-off trip, I use it regularly and want to minimise the work needed so I can go on a whim, often at short notice when the weather and tide allow. Happy to invest a bit of time into de-hassling going out and having fun.
Besides, I don't want to listen to it when I'm reversing with the boat on top, plus you can't tell if there are obstructions on the other 3 without looking at the little screen.
I've just ordered some signal yellow paint for them (front and rear). They're a bit of a leg-clonker if you walk past in a car park, but not as bad as a towbar. The rear one is actually for older models, it's the same fitting but shorter. The standard one is really long - I have that at the front but it's needed there with the bumper and lights to get past.
If you are going to leave the front one on all the time you need to check if that is allowed since if you hit a pedestrian it will hurt. A quick search on the front one suggests it might be illegal so you might want to find out.
The 3rd time you walk behind your car and bang your shin on it you will curse loudly and remove it. If your family bang their shins on it they will grow to hate you. If I had to squeeze past your car when it’s street parked I would curse. If you backed into my nice deformable bumper but because of your peculiar need to have an eccentric hole making object permanently fitted to save you a little time I would be very cross indeed. If someone runs into you I bet the chance of floorpan distorting is much higher. There is a good reason why they are designed as they are. And a good reason for the construction and use regulations. I know some people do it, but no need to add to the problem.
Why not find the thread size and insert a bolt with a D ring of some sort? Much closer to the intended bumper dimensions.
Richard_C
Current:C4 Max Hybrid, C3 1.2 Auto
Past Citroens: Dyane (x2), 2CV, Visa, BX (x2), Xantia, Xsara Picasso, C4 Picasso,C3 (x2) C5 X7 Tourer, Synergie 1.9TD, C1
Others: Hillman Hunter, Cortina Mk1, Maxi, VWT2, Granada, SAAB 900, SAAB 9-5, R5 Gordini
To me it seems odd that the op is happy to spend hours trying to disable a reversing sensor but not seconds to unscrew a towing eye. Putting a kayak on the roof rack is going to take a lot longer than the towing eyes unless that is also going to be left on all the time.
mickthemaverick wrote: 27 Mar 2026, 07:05
I would suggest you have a look around for folding towing eyes as we used in motorsport, something like this:
Mick is right - If your really want to leave the towing eye in place you could use something like this............
Folds out of the the way so it shouldn't interfere with the sensors and you don't hit you shin every time you walk past the back of the car - ad it look prettier than the stock eye.
Attachments
Stu
"Some cause happiness wherever they go, others whenever they go"Oscar Wilde (1854-1900)
Not familiar with the berlingo, but on my synergie if I had the surfboards on top I would put the tie round the spare wheel carrier basket, just bend down.
Richard_C
Current:C4 Max Hybrid, C3 1.2 Auto
Past Citroens: Dyane (x2), 2CV, Visa, BX (x2), Xantia, Xsara Picasso, C4 Picasso,C3 (x2) C5 X7 Tourer, Synergie 1.9TD, C1
Others: Hillman Hunter, Cortina Mk1, Maxi, VWT2, Granada, SAAB 900, SAAB 9-5, R5 Gordini
Richard_C wrote: 26 Mar 2026, 22:25
Why not find the thread size and insert a bolt with a D ring of some sort? Much closer to the intended bumper dimensions.
That was my previous idea. I wanted a little screwed eye. Unfortunately, although I think it is a standard M12 thread, it has a fatter part further out that's not threaded, basically just a rod about 20mm diameter. Basically the thread stops it falling out and holds it in when the fatter part meets the back of its hole when tightening. I think the thread just goes straight through, so a bolt would just sort of hang there and couldn't be tightened up against anything.
Last edited by NotAnInterestingName on 30 Mar 2026, 15:11, edited 1 time in total.
The tie-downs for the kayak are metal hooks. With the folding eye this would press into the bumper at the back or the bumper and headlight at the front. It needs the stand-off that the towing eyes provide, together with their resistance to bending.
I don't have a great aversion to removing it, my concern is that after 50 or 100 removals/refits the screw thread would probably give up.
I don't see a fundamental difference between the rear one and a towbar - it's the same concept, just off-centre. I've bought some yellow paint though.
The front one is more of a potential issue. I'll paint it yellow anyway but it may need removing between uses, I'll get some official guidance.
Anyway... good news, the rear sensor appears to have automatically re-calibrated and no longer goes beeeeep. I guess after 2 or 3 reverses it's decided that whatever that obstacle is, it's not moving relative to the sensor so must be part of the car. Makes sense, otherwise you couldn't have a towbar fitted.
The screw thread holds it in, after that fatter part behind it bumps into the front of the tapped hole. This is recessed inside a tube that's just wide enough for the fatter part. The sides of the fatter part provide its resistance to bending.
It's quite a neat design, but unfortunately this means you can't use standard bolts as there'd be nothing to tighten against.
I don't think the back one is an issue but I'm going to see if I can get a folding one for the front, I guess I'll have to put up with the strap being against the headlight.
Checked today, there's absolutely nothing that's not plastic on or under the entire front end. So the towing eye is the only way of securing the front end.
