Hi offline,
It is unbelievably simple to install the genuine factory fit kit. In actual fact I think it is easier than an aftermarket one of any type as the original wiring is already in place for it.
I have done this on a SW, however it is possible that the wiring is not present on other models of 307 like your hatchback. However I do know how and where you can check.
--------------------------------------------------------------------------
1a - On a hatchback, open the boot/trunk and pull up the floor to access the spare wheel. Just above where the numberplate exists on the inside of the car near the wheel is where the genuine factory fit ECU resides. There should be a couple of threads there for it to attach to with nuts.
1b - On a SW/Estate, open the boot/trunk and on the passenger side pull out the plastic trim behind the tool storage net located behind the rear light cluster. Just around the wheel arch look for a black 18 pin connector hidden behind the insulation. There is a single thread on the bodywork in this opening that the ECU bracket attaches to.
2. - You now need the following components from a 307 pre facelift (2005) from either a scrapyard or either by ordering from the dealer network.
a) Parking Sensor ECU; Part no 6590T3
b) Sensor loom (wiring from ECU to 4 parking sensors with a 12 pin connector)
c) 4 parking sensors; Part nos 659001 or 6590Q2 (also avail from ebay new)
d) ECU bracket (SW/Estate models only), now discontinued from Peugeot
e) Buzzer; Part nos 659002 or 6590Q2
f) Buzzer bracket; Part nos 659036
g) Sensor supports; Part no 659089 (order 4 for each sensor)
h) Sensor support rings; Part no 659090 (order 4 for each sensor)
Most of the parts above are expensive from Peugeot new so unless you have a ridiculous budget, I advise you source the complete assembly from a scrap yard on a 307 close to your age.
Note there are various ECU's available relating to different RPO/DAMs. To be clear on the parts specific to your own 307 check servicebox typing in "parking aid" into the search field.
3 - Once you have all the parts installation is straightforward. Firstly remove the centre console that runs between the two front seats. Once the console is removed you will see the following.
The circled connector is usually taped up near the front loom under the heater. Undo it and release the 2 pin black connector.
4 - Next get the buzzer assembly ready as pictured below.
You may need a couple of M6 nuts / bolts if you have none present already. Now the bracket connects to the left side at the front as pictured below.
The bracket attaches to the thread already present under the heater. A tough squeeze for fat hands but possible. Simply push the connector into place and reassemble the centre console.
5 - Now the easiest part of the installation is connecting the ECU to the 18 pin black connector already in the boot area as described in point one. If you have the hatchback use two M6 bolts to attach the ECU to the shell. If you have the SW/estate attach to the bracket first and then using one nut attach to the shell with the thread provided.
6 - Next, run the wiring loom from the boot area underneath the car. To do this, there is a rubber oval shaped bung pushed into the bottom left of the boot location (as you look into it). Push or prise it out using a screwdriver. Make a hole in the middle usiung a knife and run the cable loom through it. Now attach the bung to the car again. You should now be able to connect the 12 pin connector to the ECU inside the boot and then put your boot back together.
7 - Jack the car up at the rear and place on axle stands. Slide under the rear and catch the wiring you pushed through the boot floor. Now if you are clever no rear bumper removal is needed. There are several lugs on the base of the bumper (under the metal bumper chasis) where you can clip the wiring into place. Leave the sensors dangling for the moment while you drill the bumper.
8 - Using the measurements provided in the attached pdf for your 307, drill 4 holes in the bumper with a 25mm holesaw. In the pdf it suggests a 19mm holesaw but this is insufficient for the genuine sensors. Measure twice, cut once! I marked the bumper with a marker pen before cutting. I also removed the bumper to do this but in the previous step you can get away without doing so.
www.sog-team.com/clan/307.pdf
9 - Once drilling is complete, get back under the car and using the support clips push the sensors through into place and clip together. Ensure all cabling under the car is secured appropiately. I purchased some clips that hold the wiring onto those lugs mentioned previously.
10 - Lastly you now need Peugeot Planet to tell your 307 of your new install. I have so far only found one option in my settings but I have seen before others including visual settings on the multi function display. Sadly I fear it is not possible to have visual just sound on VAN pre facelift 307s. Go to the BSI > ECU's Present > Parking Aid > Present > Save
Everytime you engage reverse, you will now hear the parking assistance as if it was factory fitted.
Any questions please ask! I am here to help!
Matt