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Tutorial : How to Fit After Market Parking Sensors (Basic eBay Kits)

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Wed Feb 13 2013, 03:55pm
Member No: #25291
Joined: Apr 19 2012
Location: Slough, UK
Installing Parking Sensors on a Citroen C4 (Hatchback)

I saw a nice guide for installing parking sensors on a C4P, this helped me some what, but I think a guide for an actual C4 would help the community out a lot more (I know if there was one online, it would have made my job A LOT easier).

Other guides were confusing and not too detailed, this also triggered me to make one that I think would help people a lot more.


Ordered some parking sensors of eBay, there were many colours and shades to choose from.

I managed to get a VERY close match, I'm 100% happy with the colour, and you can only notice the difference when looking at the sensor and paintwork from close up. Colour difference can not be seen on camera.

Product Link : - Click Here -
(£12.95 +£0.99 p&p)

Kit contained :
x4 parking sensors
x1 control unit
x1 buzzer/beeper
x1 21mm hole saw drill bit
x1 power cable
x4 parking sensor gaskets
(Don't have a picture of the kit unfortunately)
Everything you need is in the kit minus cable ties or electrical tape (not essential)

Firstly, empty the boot, remove the boot partition panel for easier access, and remove side boot compartment walls.

(I did this as I went along, but I advise you to do it before you start the task)

Next remove the plastic clips in the picture shown below, use a flat head crew driver to pry the centre piece upwards, and the clips should just pop out.
(There are a few more that you can undo under the plastic shelf which holds the speaker, it is not essential to undo these, but it may make access a bit easier)

You should now see one plastic bolt holding the lamp cluster on, undo this by hand (or an 18 - 20mm socket will also fit), and remove the lamp.

Remove the plug by using a flat head screw driver or pointed object to undo the center clip. (Be careful, it breaks easily)

Now, under the car, near the wheel, there will be 2 plastic clips, similar to the ones in the boot that you removed. But these have flat long centre clips that you can lift up, also with a flat head screwdriver. There are 2 each side of the car.

Directly under the car, in the middle of the bumper (between the exhaust and the tow bar area), you will see a 10mm bolt, undo this.

Next under the rear arch, where the bumper separates from the rear arch you will see a hex screw clip. this is VERY hard to access, you might be able to get away with peeling the arch lining back with a wooden rod. I had to
resort to jacking the car up, taking the wheel off, removing x3 10mm bolts, and a clip. I then removed the whole of the wheel lining, just to access this one screw.

Pull the bumper away carefully and seperate the clips on the bumper that are connected to the clips on the car. Do this on both sides.

Now push the two clips on the impact block down and pull the bumper away, do this on the other side, and the bumper should completely separate/fall away from the body.

Now you will notice a wiring loom connected to the bumper for the lower lights (I think these are the lower rear fog lights, I'm not sure). I left this intact and did not disconnect them, as I couldn't see any obvious plugs.

Its long enough for you to lay the bumper on the ground at the angles required to work. (straight up as if on the car, and number plate facing down)

Next, carefully place markers (Sharpie pen markers, bits of tape etc.), where you want the parking sensors to go. I studied a few pictures online of the C4, and went for the layout below. It looks smart, stock, and is
30cm above the ground as the instruction manual instructs. (my placemnet is where the RED circles are on the picture below, other 'X' markers are other possible locations)

Drill out you're holes with the supplied bit. Not very good quality might I add. The bit was not 100% straight, so I spent 10 minutes hammering it and bending it so it would do the job cleanly.

Feed the wire, from the outside of the bumper in, and slot your parking sensors in the holes.

Note : twist then in from the front, and pull them backwards from the rear of the bumper to get a nice flush fitting.

Now, I noticed that two of my parking sensor locations (the outer ones) were on a bit of the bumper with a slight contour. Not allowing the sensor to sit flush. The kit contains gaskets/washers for this purpose, one end being thicker, one being thinner, allowing the parking sensor to sit securely.

For any strange contours, you can trim the gaskets to your liking, these have also been colour coded, so they do not look out of place.

Sensors should now be all fitted with the wires trailing into the boot:

It was at this point it started snowing and must have hit 0oC outside. As a result I got a strange error on my phone, looks like Android smart phones are prone to head colds (or it may have been a limitation with my own custom ROM)

Anyway, didn't get too many pictures of the actual wiring as, the mobile stopped working, and threw me a weather warning even when I tried to use the camera without the flash.
So what I've done is transposed the wiring layout on to a picture of the rear of the car. (excuse the quick MS Paint jobby)

Use cable ties or electrical tape as needed.

You can now go ahead and put the bumper back on, along with all the fittings.
*Hex screws at under the arch
*Clips on the impact blocks
*Clips under the car (corner of the bumper)
*Nut in the middle of the bumper, under the car

Now to connect the power you need to solder the +ve and -ve terminals hanging out of the top of the bumper, to the reverse light. Dismantle the light fitting, there are a few clips and solder the power wires to the 12v
source, and the other to Ground. You will need to scrape away the oxidised coating to get a good contact.

Note: I have my wires mixed up below, the red should be in the place of the black, and the black should in place of the red.

Now the buzzer, this can be fed through the bumper, under the boot seal, behind the boot carpet, and near the lamp fittings black bolt, stick down with the 3m double sided tape supplied.

Note, this could also be fitted near the control box, inside the bumper. It could also act as a lorry/truck reversing tone, and could probably still be heard within the car as its loud enough.

Put the lamp fitting back together, and secure back to the car. Replace the boot carpet clips, the separation panel that your first took out, and the side compartment partitions. Along with any other mess that was originally in the boot.

Finished product pictures to come tomorrow, when it's light enough to get decent snaps.

[Admin edit: Images resized in accordance with forum rules.]
Edit 16/2/13 : Grammar + added a step (missing bolt)
5 User said Thank You to Mk3_Singh for this Post :
 Citroening (13 Feb 2013 : 16:09) , wilcovh (13 Feb 2013 : 16:31) , Dave_Retired. (14 Feb 2013 : 04:49) , Biohead (14 Feb 2013 : 11:11) , k3dad (03 Oct 2018 : 18:16)
Wed Feb 13 2013, 04:37pm
Member No: #28996
Joined: Jan 19 2013
Location: home
are they already made holes in the black bit for the sensors ?
does the vtr + come with those pre-cut holes ?

Wed Feb 13 2013, 04:46pm
Member No: #27768
Joined: Oct 13 2012
Location: Hove
I thought that too!
Wed Feb 13 2013, 04:58pm
Member No: #25291
Joined: Apr 19 2012
Location: Slough, UK
@watercooled, there are guide holes (not actual drilled holes) for 2 sensors on the black central trim on the bumper, however I ordered a red kit, and that would look odd (red sensors on a black plastic trim)
would have looked like this:

There were also no blank sensor holes where on the outer sides of the bumper, so I put them where they would have been on a VTS (I believe)

[Admin edit: images resized in accordance with forum rules]
Wed Feb 13 2013, 05:02pm
Member No: #28996
Joined: Jan 19 2013
Location: home
Thanks for the info.

I will check my VTR+ tomorrow and if it has 4 guide holes, I may do this myself.
Thu Feb 14 2013, 04:26am
Member No: #25291
Joined: Apr 19 2012
Location: Slough, UK
Check and let me know if you have the outer guide/blank holes ... my car may have had a bumper change at one point (possible accident) ... or it might be the higher end models with a different bumper that have the outer ones ?

Its an easy job one you know what your doing, took me 7 hours, you'll do it in 1.5 - 2 with this guide.

Kits were £12.99 of ebay brand new, with a choice of 70+ colours ... not sure if I'm allowed to link to ebay sellers, but he's easy enough to find, he's the one based in Slough, Berkshire.
Thu Feb 14 2013, 05:35am
Member No: #28996
Joined: Jan 19 2013
Location: home
I have the 5 door VTR+ and don't have those holes.
Thu Feb 14 2013, 02:27pm
Member No: #5593
Joined: Sep 29 2008
Location: Northern Ireland, Lurgan
I don't think that there is a problem with posting the link. Others have done it before for buying new fobs from ebay.

So the WHOLE kit is £12.99? And you don't need anything extra?

If this is the case then I think I'll have some of that. And with this excellent guide you have made, it might be a doddle. I think Dave will be appreciative of this tutorial.
Sat Feb 16 2013, 03:30pm
Member No: #25291
Joined: Apr 19 2012
Location: Slough, UK
Yep, don't need anything else at all.

Even comes with the drill bit you need to make you're 21mm holes (does the job even if it isn't the best quality).

Only thing that you'll need (purely for aesthetic reasons) are cable ties or some good electrical tape to tidy up the wiring, e.g. convert the 4 separate sensor wires into a single bundle.

comes with good quality 3m double sided tape, all for 12.95 (+99p p&p)
Sun Feb 17 2013, 05:27pm
Member No: #5593
Joined: Sep 29 2008
Location: Northern Ireland, Lurgan
I am assuming that these are just universal parking senors and will not connect to the head unit or display the information on the screen? This would explain why the Citroen ones on ebay are 10 times the price.

Mon Feb 18 2013, 05:32am
Member No: #21107
Joined: Jul 31 2011
Location: Ruislip, Middlesex
connormoose wrote ...

I am assuming that these are just universal parking senors and will not connect to the head unit or display the information on the screen? This would explain why the Citroen ones on ebay are 10 times the price.

Exactly. If you can live without the visual radar display, definitely worth considering. However, the genuine article will not only interface correctly with the car over CANBUS, but will also give you the visual display along with the audible one.

Note: I think Citroen also does a basic retrofit pack that is audio-only, sure I saw someone post on here about it last year.
Tue Feb 19 2013, 07:16am
Member No: #25291
Joined: Apr 19 2012
Location: Slough, UK
connormoose wrote ...

I am assuming that these are just universal parking sensors and will not connect to the head unit or display the information on the screen? This would explain why the Citroen ones on ebay are 10 times the price.

No visual aids on the screen in the C4, purely an audible signal.

I see no point in this though, when reversing you instinctively look behind anyway, and check your mirrors.

I don't know of any sensible driver who looks ahead and purely monitors their parking sensor screen when reversing.

When looking back, you KNOW what you are about to hit/scrape (you can physically see it). All this parking sensor does, is notify you of how far away you are from what you are about to hit.

4 sets of tones, the quicker the tone gets the closer you are to an object, at a steady "beeeeeep", you know to stop completely as you are 30cm - 0cm away from an object.

However, there are kits on ebay that come with screens, leads, and distance meters. These do not fit the Citroen's interiors. Red, amber green LEDS, with old school LED style numbers, would look horrible in anything over a P Reg.

I'll try and get a youtube video up when I next take the car out.
Sat Jun 28 2014, 04:47pm
Member No: #11964
Joined: Jan 05 2010
Location: Glasgow
When I fitted mine, I just spliced into the wire going into the reversing lamp. Not had any problems.

Always great to see pictures along with a tutorial.

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