Inconsistent reverse sensor beeping.

JustAnotherSaver

It's going to be some months before i can get to someone who will deal with reverse sensors so in the meantime I thought i'd ask here in case someone has a clue.

I bought my car (2006 Mondeo ST TDCI) about July/Aug last year. I don't know if reverse sensors are standard with these cars but I see a lot of them with them. Why I say i don't know if they're standard is because the install looks pretty bloody shoddy. The plastic trim that runs down the passenger doors at the carpet level wont pop back in place, so on the rear passenger side you see some wiring underneath. In the boot you see a black box which just sort of flaps and flops about.

When I bought the car the reverse sensors didn't work at all. I had a look at this box in the boot and the wire wasn't connected to PWR so i figured that was it - connected it up and still didn't work.

Then a week later it started working randomly but when you took it out of reverse it made a sad sounding beep that sounded under water kind of thing. Hard to describe. Not actual under water but like it was running out of batteries.

This lasted a day and half and then it stopped working again - for say a month or so. Then it randomly started to work for a few month before stopping working again for a while. A few weeks ago It actually stopped working while it was in reverse (all the other times it's worked fine but then the next time i come to select reverse, it doesn't beep).

So in short it's very on & off.

The paperwork that came with the car states speedsafe co.uk parking sensor.

Photos of the unit:

Any idea why it's randomly working and then not, and then yes and then no .... and repeat?

molerat

Looking at the state of it makes me think wet, either is getting wet now or has been at some time and the electronics are goosed

AdrianC

That's an aftermarket install, not factory. And the paperwork even states as much... speedsafe.co.uk now takes you to rewiresecurity.co.uk - a quick look at archive.org shows the domain was for sale in 2013, having started off as a retailer of radar detectors and similar.

They won't have manufactured the kit, though.

But now you know why they disconnected the power. It's knackered.

JustAnotherSaver

I'd be interested in looking at a 'proper' install as this looks VERY it'll-do-DIY.

The design of the boot I've found with this car is also pretty poor when it's been raining. It's OK if the boot stays shut but open it and the water runs direct in to the boot. Poor design.

Obviously you've not seen it yourselves but from the limited info do you have an idea what would be a fix on the job? Does it sound like I just need whatever that black box is, but a new one? Or am I likely going to need fresh wiring front to back plus a new box?

Was never that bothered by reverse sensors but they're pretty handy on this car so would like reliable ones. 

molerat

Likely only realistic option is to replace the whole lot, it is quite old and unlikely the same parts are available. Could you even get the box separately except second hand ?

Yes you do get used to them  but can get into the bad habit of not looking behind when reversing.  I have them front and back (and side) and they are really handy, besides that the car couldn't park itself without them

greyteam1959

You can buy the whole lot on eBay for about £15 delivered.
If you don't want to replace the sensor's in bumper just use the box & the beeper.

ilikewatch2

Before doing anything else I would check:
a) That the cars reversing lights are working OK - the parking sensor control box almost certainly takes it's power from a splice into this circuit. Also check that the splice is good.
b) That the control box has a good earth.

JustAnotherSaver

Is any old box likely to do/be compatible with the current install? This is basically the impression i got from what @greyteam1959 said.

The reverse lights work no problem. Regards other electrical questions, I will at some point be having to ask someone how to even use the multimeter i bought so i can test out the issues i'm having with a dash cam install. In other words, electrics is probably the area i struggle with the most.

As for getting TOO used to them - not likely. That puts you in the bracket of "but the dashcam told me to drive off that cliff" type of people. I used them as an aid only. I still look out of my rear window and use wing (ok ok, side) mirrors and if i'm still not sure then I just get out and check. I've had to do that a few times lately. The car is a bit large for my wife to drive too so she would benefit massively from working reverse sensors.

bob_a_builder

JustAnotherSaver said:

Is any old box likely to do/be compatible with the current install? 

They might be they might not be ! 
I just did the same to one of our cars - my old install had gone bad is a similar way to the OP - random beeps  - decided to change the whole lot 
The inside of your boot maybe damp, but the back ends of the sensors are generally in an even damper place !

New kit was  £10 for China 

A couple of differences between old and new 

Whilst the power plug/socket was the same type - it was wired opposite so could not  just plug in had to swap lead over

The sensors were a tad bigger diameter, was able to enlarge hole using the saw too provided, but because the saw had a 5 or 6 mm centre drill mounted in it   - but I already had 20 mm holes -  it was tricky to get to saw to work right - probably a file would be a safer option
The new sensors also had some silicon rubber 'teeth' to hold them into the bumper which I needed to trim down a bit to suit thickness of bumper

The new one had a dashboard display which also houses the beeper - you ca choose to mount the display up front or not bother with hassle of running cable thru the car, and just leave it in the boot and rely on the buzzer

One I had it wired up, I put the lot inside a plastic bag and sealed it up with tape, fitted in behind rear light trim inside boot

https://www.ebay.co.uk/itm/Reverse-Parking-Sensor-Rear-4-Sensors-LCD-Display-Audio-Buzzer-Alarm-Kit-Silver/184304984525

AdrianC

bob_a_builder said:

The sensors were a tad bigger diameter, was able to enlarge hole using the saw too provided, but because the saw had a 5 or 6 mm centre drill mounted in it   - but I already had 20 mm holes -  it was tricky to get to saw to work right - probably a file would be a safer option

Clamp a piece of wood behind the bumper, and drill into that.

bob_a_builder

Clamps
Given the size and odd shapes of bumpers and general inaccessibility behind them, not sure that's really practical ?
I managed to hold it ok but there is very high chance of damage trying to extend an existing sensor hole with a hole saw tool

Another option might be to glue a thin piece of wood across the rear of the hole ? If you can get the backside of the bumper clean enough to give the glue a chance