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Discussion Starter #1
Well, decided to look at my none working rear sensors. Got a bit temperamental about a year ago but have given up the ghost completely now.

No messages on the dashboard or diagnostics so I thought, bumper off and check for broken wires or something obvious.

Have had the front bumper off to repair washers and that was pretty straightforward so expected rear bumper to be similar.

Some hope. Twenty six fasteners of various types, twenty four of which undid fairly easily, one was a complete pain but eventually freed, but one, the most difficult to access, would not budge. Tried drilling the head of the bolt off but gave up, now half way through hacksawing through the bolt with only one inch of sawing movement, until got rained off.

Will eventually get there but even at this stage I can see all the wiring and there is nothing as obvious as I had hoped for so all the effort could be for nothing.

When I eventually get the bumper off, I'll check and clean all the connections, but if that does not work anyone any suggestions what I should look foor next?
 

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Discussion Starter #2
OK, so no responses to my first question so can anyone answer this?

I expected to find the parking sensor control box behind the trim in the boot but all there is, is a small connector, size of a 'Tic Tac' box. Presumably there is more than this but can anyone tell me where it is?
 

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Is the tic tac box a connection box for all the sensors? You could start by disconnecting them and testing them individually.
 

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Have you tried listening to them. If they work like others (worked with my Saab) then when they are engaged they should have a low volume tick from each sensor. Ear right on each is a quick check to find out which one could be faulty.
 

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Discussion Starter #5
Have you tried listening to them. If they work like others (worked with my Saab) then when they are engaged they should have a low volume tick from each sensor. Ear right on each is a quick check to find out which one could be faulty.
Yes, but no 'ticking' from any hence my assumption that a wire must be broken or control box faulty.

No obvious broken wire, still looking for something resembling a control box.
 

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On the 159 SW, the box is low down in the rear right under the rear fuse box - pain to get at.
My outer left is playing up and I get the Parking Help error message.
The fact that you get no message at all points at something other than the wiring under the bumper (fuse?)
From what I discovered, a broken or disconnected wire sends an error message.
 

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Discussion Starter #7
The fact that you get no message at all points at something other than the wiring under the bumper (fuse?)
From what I discovered, a broken or disconnected wire sends an error message.
Can't be the fuse because the same fuse serves other circuits and they're all OK but don't understand why there is no error message.

After removing and cleaning with contact cleaner one of the sensors seems to have come back to life so have ordered a couple of new ones to check on the possibility that all four decided to call it a day at the same time. Unlikely but hey, it's an Alfa.

Still can't understand why no error messages.
 

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I thought there was a dedicated fuse in the rear??
 

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Discussion Starter #9
I thought there was a dedicated fuse in the rear??
According to my handbook it is fuse F49 which also safeguards up to ten other circuits.
Can't find any mention of another fuse.
 

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Discussion Starter #10
Two new parking sensors arrived this lunchtime, £10 each post free from Poland.

Fitted them this afternoon and both work OK. Need to get two more now, maybe.

Problem now is that the display between the two main dials is now acting up.

It has done this before and I have taken the column stalk switch to pieces and cleaned it and then all OK.

Cleaning has had no affect this time so could it be the new sensors or is it just coincidence?
 

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Discussion Starter #11 (Edited)
Beginning to understand why they were only £10 each, genuine ones are over £80.
Not only is the display misbehaving, but only one of the main dials (speedo) is backlit. Don't remember the tacho not being backlit before but then I don't go out in this car much in the dark.

Rear bumper off again tomorrow and new sensors disconnected to see if they really are the cause.
 

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Beginning to understand why they were only £10 each, genuine ones are over £80.
Not only is the display misbehaving, but only one of the main dials (speedo) is backlit. Don't remember the tacho not being backlit before but then I don't go out in this car much in the dark.

Rear bumper off again tomorrow and new sensors disconnected to see if they really are the cause.
Veloce's are selling the entire kit for £72 (+P&P): Alfa Romeo Part Shop | ACCESSORIES | REAR PARKING SENSOR KIT for 159 ALL MODELS from Veloces of London
 

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Discussion Starter #13

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Discussion Starter #14
This morning went to revisit the reversing sensor problem and found the back-lighting to the tacho was working again (not working last night) but that the menu button on the left hand stalk was still not working properly.

Not sure if this was caused by the new, super cheap sensors (all on same fuse and circuit I believe), or just coincidence in that the menu stalk had already been acting up for a couple of years. So, off came the bumper (all fixtures now freed and I'm well practised so only takes me just over twenty minutes). Old sensors refitted so now I have no reverse parking aid and menu button is still not working properly although the screen is not rolling over as it was yesterday.

What I don't know is, have the new sensors upset the apple cart or is it just coincidence and the menu button was going to act up anyway?

Oh! and have the Chinese started turning out copies of the column stalks yet or do I have to pay an Alfa dealer £400+ for one?
 

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Discussion Starter #16

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Discussion Starter #17 (Edited)
After a week away from my parking sensor and menu stalk problem I decided to have another look at the none working menu button.

I dismantled the relevant column stalk, removing the buttons and easing out the circuit board. Even when operating the micro-switches directly, the display still had a mind of its own.

As a last resort I by-passed the switches by placing a screwdriver blade across the soldered joints on the circuit board and, surprise, surprise, the menu started to come back to life and is now working as it should again. :surprised: Don't ask me why or how.

Question is, what do I do now?

Leave well alone and manage without reversing sensors.
Spend £160 on a couple of genuine Alfa ones from Alfa Workshop in the hope that they should not cause problems.
Or try the ones linked by swq4 on Ebay advertised as genuine Alfa at £15 each. :nervous:
 

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Discussion Starter #19
when i had one on mine fail, i bought the cheapest one i could on ebay
looked like http://www.ebay.co.uk/itm/1x-Fiat-C...el:159&hash=item281514949d:g:ClMAAOSwJQdW-J1s

painted it, and it worked fine.
if the 2 you bought are now clicking, id get another 2 cheap ones, and give it a go.
odd that you dont get an error message that they arent working though.
My cheap Ebay ones worked fine, they just seemed to send my menu screen bonkers.
Maybe the fact that I'm getting no malfunction message suggests that there is something a little more sinister going on with my car.
 

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Discussion Starter #20
Rear bumper off again today (down to a fine art now) and two new 'genuine Fiat' ,£15 each, rear parking sensors fitted.

Work as they should but, weirdly, the information panel also works, which was not the case when I originally fitted two £10 sensors.

Don't know if this is coincidence or an Alfaism but that seems to be another job sorted.

Just waiting for two new fog lamps to be delivered and now that the front end has been resprayed, cosmetically at least, my ten year old Brera will be ready for NAD which is just down the road at Chatsworth this year.

Just need to find a garage now that can diagnose and cure the lumpiness in the engine at low revs (below 2500).
 
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