Parking Sensors are a useful accessory and can be obtained from car shops or ebay and they will cost considerably less than those supplied by Mercedes.
Most of this post has been gleaned from public & private posts submitted by forum member " TROUT " whose help has been invaluable in setting up sensors on my own car.
Firstly this information is intended to tailor the sensor manufacturers instructions to the B Class & not to replace them. If your kit says do something differently then do it as the instructions say.
It is a reasonably fiddly job but the average DIY enthusiast should be able to tackle it. I would strongly recommend that two people do the job, it's tricky doing it on your own.
1) Spray the sensors with 3 or 4 thin coats of car coloured aerosol spray.
2) Decide where you would like to mount the control box, bear in mind the lengths of cable that are fitted to the rest of the periphals. I fitted mine in the rear compartment that holds the first aid kit & owners manuals.
3) Chose where you want the buzzer. I fitted mine on the drivers side door pillar.
Again watch those cable lengths you can use a lot of cable getting from one side of the car to the other. My cable fed round the back seat under the carpet and required lifting the plastic trim that is on the floor behind the back seat. The wire was then fed under the trim & rubber on top of the door sills. It fed under the rubber up the side of the door pillar to the buzzer which was secured with the supplied sticky pad. If you have an LED display fix this to the dash in a convenient position taking the cable past the front door & up the wheel arch.
4) Sensor fitting (ensure the paint has had day(s) to dry.
You will need to remove the rear bumper to fit the sensors this is where 2 people are handy. On the inner wheel arch protector there are a couple of plastic plug type clips, you need to prise the centre pin out a few mm with a flat screwdriver and then pull it out completely with either your fingers or a pair of pliers, then pull ot the rest of the "plug". This gives you room to get at the 8mm socket headed bolt that holds the "pointed" end of the bumper to the wing panel. When this is undone this "pointed" end snaps out of some hidden clips. It might pay to put some masking tape on the bottom of the wing to stop it getting scratched.
There are 4 x 8mm bolts on the underside of the bumper to remove.
The top of the bumper is held by 4x 8mm bolts that are hidden under black plastic "plugs" these are near the loading area & up by the lights, use a small screwdriver at the bottom of these "plugs" to prise the plug out.
With an assistant holding the bumper undo the bolts and gently pull off the bumper.
The bumper is quite flimsy & easily scratched when off so it is probably a good idea to do the rest of the work on it with an old blanket underneath.
The 4 sensor positions are marked with a cross inside a circle within a something resembling a TV screen. Drill or ream a very small hole from the inside of the bumper. Then turn the bumper over and using the supplied holesaw (with a fairly slow speed electric drill) drill the sensor holes from the outside of the bumper.
Clean up the inner and outer edges of the hole.
Fit the sensors in the order that is given for them in your instructions. I used a glue gun inside the bumper to lock the senors firmly in place.
I used plastic straps to keep the sensor leads together inside the bumper.
Under the corner of the car is a large rubber grommet (about 25mm) pull this out and cut a + in it and feed the cables through it . Feed a piece of stiff wire up through the grommet hole and this will come out in the forementioned "cubby hole" Tape the longest sensor cable to the end of the draw wire and gently pull all the sensor cables through.
5) Power feed:- this comes from the reverse switch in a Yellow/ Grey wire and it can be found on the right hand side (looking from the front) of the car in several places in a black wiring loom. It comes under the trim on the rear door sill up into the hidden pocket that holds the jack & toolkit and then up into the roof. Your choice where you want to join it up (I think TROUT connected his in the roof with the warning to watch that the white mastic does not get on the roof lining).
I chickened out of that as I don't like messing about with roof linings and opted for the Jack compartment. I stripped a bit of the yellow/grey wire back & soldered a wire to it and then covered the joint with sleeving & tape. The other way of joining is to use a special connector that crimps through the insulation without disconnecting the wire, your choice.
I ran my wire through an inline fuse (using a 1 amp fuse) and I picked up the earth connection from under one of the 2 nuts that are behind the manual pack in that rear compartment.
6) All that is left to do is plug in your leads to the control box ( ensuring correct polarity of all leads).
7) Refit the bumper in the reverse order to that stated in paragraph 4.
8) Test the system with the ignition on (engine off) & car in reverse. If you walk round the back of the car it should beep as per instructions.
Job Done !
Good Luck
Many thanks are due to TROUT for sorting out the technical aspects of this job and his prompt replies to my questions on the fitting of this unit.
Well done Keith. I never thought it can be done. Now I am really tempt have to sensor but I am not ready to DIY. Maybe I can team up with BeeClass.
BeeClass, LMK if you are interested since we live in the same city.
BTW, I notice this thread was created back in August. How come I didn't read about this back then? I notice there are no instant reply notification emails lately. Is there anything wrong with the forum?
Keith, can you tell where you bought the sensor? Is there front sensor also? I know the one BeeClass got has six.
There is a type of sensor that is stick-on, no drilling is required. Any idea on how to hide those wires leading to the sensor head? With the drilling type, wire is hidden behind the drilled hole leading to the sensor head.
My sensors were bought on ebay there were masses to chose from there.
I chose the 4 sensor rear only type with just the buzzer. I like to be able to check all 3 mirrors as well whilst reversing so I did not think the LEDs or other types of display were worth getting, but this is a purely personal thing others may think they are a necessity.
The sensors seem to work reasonably well you get a beep when you engage reverse gear which is handy as once I knocked the (auto) lever into reverse without realising it.
You do get the occasional spurious beep whilst reversing and also (somtimes) with frost or water on the sensors you get an odd beep or two, but these are not in the same pattern that you get when something is behind you so you soon get to recognise these.
This may be a 'glitch' that only appears with my make of sensor.
Any one else had this happen with their sensors.
On the whole well satisfied, I think they were just over £20 with about 4 hours work. Any one who is an average DIYer or home mechanic should have no problems.
I have a link to the 'official' bumper removal information if any one is interested.
Can you send me the pdf instruction? I also like your sensor with buzzer only. Can you provide link to that as well? I find one on Ebay with buzzer only but it is the stick-on type and no drilling is required. I wonder how good this type is.
The stick on sensors may be easier to apply, but they could fall off, be torn off by vandals etc and the wires would look ugly.
Do yourself a favor and get the holes drilled.
Can you send me the pdf instruction? I also like your sensor with buzzer only. Can you provide link to that as well? I find one on Ebay with buzzer only but it is the stick-on type and no drilling is required. I wonder how good this type is.
PMd the info regarding bumper removal to you
My unit was bought some months ago from someone who only had a few left & was located in the UK. I am sure there must be some available somewhere on the Can/ Am ebay site.
Note they usually come with a holesaw to give the exact sized hole for the sensor & on the inside of the bumper the correct positions four the 4 sensors are marked. You only need to drill a small pilot hole (say 1/8") from the back of the bumper to the front & then use the supplied holesaw to drill from the front of the bumper this way you get a neater hole with no paint cracking etc. I would personally not go for the stick on version to my mind it is a bit of a bodge & may affect your resale value IMHO.
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