Parking/reverse Sensor

[stadsy]

Hi everyone, I've got a 2004 C-Max manual 2.0d, which I love, but I'm having problems with the reverse sensor. The trouble is, it has stopped working, my Mrs usually drives it and she told me recently that she could just about hear the reverse alarm, but of course now it has stopped completely. I have wd40'd all connections, to the sensors, control module etc. The module says Ford on it. Reading other posts, it was mentioned about fuse 84, this has been checked and is fine. Reversing lights all work, and all wiring seems to be in order. Is there a way of checking the sensors? or have I missed something obvious. Just though I'd ask, before I bite the bullet and take it to a robbing thwaite. Help please.

Stadsy

[jeebowhite]

Welcome to the family Paul

OK, so do you have reverse lights on at all?

[stadsy]

Hi,

Yes mate, all reverse lights work.

[jeebowhite]

OK so in that case I would suggest its a power / earth fault.

Can you track the wires down, you should have an earth cable that goes to the earth bolt in the boot area, and also the power cable that should split off from the reverse light wire? are they both there and secured?

Also, it could be the buzzer unit thats stopped working if the above is fine...

[stadsy]

Hello again,

Just checked all wires looking for an earth and there doesn't appear to be one in the boot area, or underneath. I had the ignition on with the car in reverse while I checked all wires, and discovered the sensors vibrating, which would suggest power supply is reaching them. Just removed sounder and connected it to my bike battery and it worked!!! The only earth would be where the sounder is bolted to the right side bodywork. Hmmm. Gonna bolt the sounder back in and check power supply to the sounder. This is cooking me.

[jeebowhite]

Sounds like everything should generally work. But the bolting to the bodywork should definately be there!

[stadsy]

Hi again,

It would appear that the reverse sounder I was checking, turned out to be the alarm horn!!! Hmmm big red face, the sounder for the reverse sensor was not working, I tried a speaker improv and it worked. Massive sense of relief, as my mrs tends to rely upon them. I ordered one for just over £8. Thanks for all your help, you did suggest the sounder this morning.

[jeebowhite]

Glad to be of service Paul :) a new buzzer for £8 isnt bad at all, even a temporary fix with a cheapo buzzer or a computer speaker at the moment is something that could get you by!

[1978danno9]

Hi, i have a C-Max 2005 2L Diesel Manual. Both the front and rear reverse sensors have stopped working, the front went first and then the rear recently. Also both the reverse lights are not working. I have been to Halfords over the weekend who have suggested that it could be the reverse switch? The parking sensor on the dash is highlighted as 'off' and does not change when pressed. Can any body please help?

Many thanks in advance

[Caiti]

Sorry I cannot help but have a problem with mine also 2004 1.6 diesel automatic. Mine do not work when reversing but seem to beep randomly at other times e.g. when I go over a speed hump. Hoping someone replies to your post. In the meantime I think mine started to go wrong after I washed the car and there is something in the manual about not directing water spray at them

Caitriona

[jeebowhite]

Karen, apologies I have just seen this, I saw it before and seem to have forgotten to reply!

The reverse switch is a distinct possibility. If you put the car into reverse, do the reverse lights come on? if not / intermittant, then its most likely the reverse switch. It is a DIY job and there is a guide in the Focus section for replacing it yourself, but otherwise a garage could sort it.

Caiti, sounds like you might have had water ingress. are they aftermarket or OEM sensors?

[Caiti]

I believe they are OEM but have not had it from new

C

[jeebowhite]

do you have an on off switch on the dash for the rear sensors?

[Tilly1989]

I brought a Ford c max 56 plate and I went to you the the sensor but the light is flashing on the dashboard and there is no sound when I get close to something at the front or the back of the car could it be water in them or a fuse . Thank in advance 

[unofix]

Hello Tilly1989. welcome to the Ford Owners Club.

Please start by completeing your member information, Model, Year etc.

Asking for help in a 7 year old post is not likely going to get you much response. Start a new thread explaing the problem in full, what light is flashing on the dashboard?