W203 (pre-facelift) parking sensor advice

rayfenwick

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Hello all.
I've been quiet for a while, but I'm back with new questions about a new car - a W203 estate I recently purchased on eBay. I am hoping to sort out some small problems and perform some upgrades - first of which is add front and rear parking sensors. I've found a donor vehicle and the seller is willing to post the bits, but can someone please tell me exactly what bits I need?

Of course the bumper inserts with the sensors in, but presumably they connect to some control unit(s), but is there anything else a display or speaker unit in the dash?

Sorry to sound impossibly clueless, but I am in Moscow and the car is in Hull and I'm having to do everything remotely...

Thanks
Ray
 

whitenemesis

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My advice would be to go 3rd party aftermarket kit. Far less hassle and cheaper both to buy and to fit.
 
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rayfenwick

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Understood, but I'd much rather fit the proper stuff if I could. I have a technical background and also brother's friend is ex-Main Dealer mechanic and has all the kit including star, so between us we should be able to sort it.
 

richard

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a) Front bumper/strips and sensors
b) Rear bumper/strips and sensors
c) Front bumper loom
d) Rear bumper loom
e) Main loom (probably best bought new as pretty much impossible to remove)
f) looms going to displays (probably removable, maybe rear one is part of main loom)
g) Front and rear displays and mounting brackets
h) ECU (on back of footplate in passenger footwell) and mounting bolts

There are various clips that hold wiring loom connectors in place (in particular the bumper connector points)

R
 
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rayfenwick

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Ok, that does sound like a lot of work. Are you saying that the main wiring loom for the car would need replacing?

In previous experience of car looms, the 'option' wiring is there in the main loom, with connectors to plug in the options. It doesn't make much sense for a main dealer to have to send a car back to the factory because the customer has changed their mind about headlight washers...

Perhaps I misunderstood?
 

richard

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Ok, that does sound like a lot of work. Are you saying that the main wiring loom for the car would need replacing?

In previous experience of car looms, the 'option' wiring is there in the main loom, with connectors to plug in the options. It doesn't make much sense for a main dealer to have to send a car back to the factory because the customer has changed their mind about headlight washers...

Perhaps I misunderstood?

You don't need to replace the main loom, there is a parktronic loom you need to add. It goes from front bumper to rear bumper to control unit, displays and to fusebox.

There is no optional wiring in a Mercedes. This is because (a) cost, (b) different combinations of options use different wiring. For instance Xenon vs non Xenon wiring completely different. (c) *so* many possible options

The manufacturers don't want you to add stuff, they want you to buy a new car.

Other manufacturers such as Kia basically have 4 different wiring looms for the 4 different specifications you can buy. Again, nothing spare in there

Richard
 
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rayfenwick

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You don't need to replace the main loom, there is a parktronic loom you need to add. It goes from front bumper to rear bumper to control unit, displays and to fusebox.

That sounds more likely, thanks. I'll pass this on to the guy with the donor car.

There is no optional wiring in a Mercedes. This is because (a) cost, (b) different combinations of options use different wiring. For instance Xenon vs non Xenon wiring completely different. (c) *so* many possible options

Ok, but isn't that the opposite of what you're telling me above? That there's additional wiring for the parking sensors system that plugs in? Most cars I've worked on have (for example) wires in the main loom for rear wiper even if there's no wiper at one end (or switch at the other...) Or upgrading from manual to electric rear windows just by plugging a suitably equipped rear door into the connector?

The manufacturers don't want you to add stuff, they want you to buy a new car.

Of course, but not if you've just bought a car from the main dealer and then decide to have an option fitted by them! That's the reason for the level of electronics these days - so everything can be controlled by the manufacturer and its approved dealers, cutting out 3rd parties who may have the correct parts but can't 'tell the computer about them' so they won't work.

Other manufacturers such as Kia basically have 4 different wiring looms for the 4 different specifications you can buy. Again, nothing spare in there

This is the opposite of what was going on when I studied this. The industry was moving towards reduced and multiplexed wiring with the various ECM's for different engines and equipment plugging in to a standard backbone loom and a central, common brain that could be dealer programmed to enable/disable everything. This was one of the main reasons for CANBUS, for example. Bespoke wiring harnesses are very last century, surely? :dk:
 

richard

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> Ok, but isn't that the opposite of what you're telling me above?

I don't think so. There is NO parktronic wiring in your car. You don't have to order a whole new loom with the parktronic wiring and everything else for your car, Mercedes sell replacement wiring just for the parktronic system. I expect its about £150.
However, when a car with parktronic is built, that loom is just part of the main loom so extracting it will be impossible as it is all wrapped into the main loom.
If a car needs a new loom, you order it by VIN number and they go make it.

> Of course, but not if you've just bought a car from the main dealer and then
> decide to have an option fitted by them!
Answer from main dealer is "unless its an approved retrofit then no can do". Approved retrofits tend to be for Satnav, Reverse camera, etc.

> That's the reason for the level of electronics these days - so everything can be > controlled by the manufacturer and its approved dealers, cutting out 3rd
> parties who may have the correct parts but can't 'tell the computer about them' > so they won't work.
And legislation in US and EU force manufacturers to make the diagnostic equipment available, and actually there are pay-as-you-go options that aren't hugely expensive for some limited level of diagnosis. (see passthru devices)

The reality is that you need people who both understand auto-electrics and computers to deal with car electronics now. That is why many main dealers have trouble diagnosing complex faults and can not retrofit stuff. The info is there is their workshop manuals about what communicates with what, but you can't ask the electronics parts catalogue "give me all the bits needed to add option X" - unless it is an approved retrofit. Also, different people work on the cars to those that order the parts. And you don't want to be paying >£150/hour for them to try and work it out from the workshop info and the parts catalogue unless its a relatively simple thing

>This is the opposite of what was going on when I studied this. The industry was >moving towards reduced and multiplexed wiring with the various ECM's for

This is going on, it is just the complexity has stepped up again alongside the cost consciousness. If it wasn't for CANbus etc in cars they would not have the functionality they have to have now. In fact there is ethernet appearing everywhere now too.

If MB wired their cars with connectors for every possible option, it would be a few hundred $ per car extra (probably just in wire!!) and no one is going to let them do that for the very small amount of retrofits that actually go on.

Bespoke harnesses are also needed because the specialist cabling between control units and the sensors is specialist (and because of the complexity, expensive). Think of video cable (shielded), USB cable, etc

It would be lovely if every sensor / control unit just had power and ethernet on it and all you do is just run a cable to the sensor back to the nearest hub/switch
- But at $1 per chipset for ethernet and $0.10 for LINbus and $0.30 for some cable, you know what they will chose.

(so if you think about parktronic, there is 10 sensors, one control unit, 2 displays), yes the control unit just interfaces to the rest of the car with power and CANbus, but all the sensors and wires are hard-wired to the control unit.

My KIA example was because that is an example of a manufacturer that is very careful with ensuring the "this is great value with a 7 year warranty" and they do the "no options can be added, and there is nothing spare in there i.e no extra cost" - so my suspicion is that the real volume manufacturers are doing the same - but I haven't checked since I tend to only look at Mercedes (but my Mum bought a Kia and I wondered whether I could put the nicer headlights on it)

Cheers

Richard
 
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rayfenwick

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Thanks a lot for your help and advice Richard, it is very much appreciated. I remember adding Cruise control to my Citroen XM by getting the lever from eBay and plugging it in... :)

I've sent your parts list to the guy with the donor car - hopefully all will be well. Next step is an interior facelift and COMAND installation... (and all before the other half finds out about the upgrades :) )

Best wishes
Ray
 
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rayfenwick

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After all that, his prices went too high, so I'm looking elsewhere for bits! :(
 

whitenemesis

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I suppose there's a lot of dismantling of the donor car involved, if one wants all the bits intact
 
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rayfenwick

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Yes, perhaps a lot of work to go through for not much reward for the seller...
 

Dave Richardson

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I fitted an after market set of (Cisco) sensors to my CL203 purchased from a from e bay seller & they have worked fine for the last two years. In the autumn of last year I fitted a front set & they are a nightmare and keep going off at every light braking or above 30mph, I landed up fitting a simple on/off switch under the dash board. Now are switched off for most of the time
D
 
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rayfenwick

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Sounds like a nightmare until you fitted the switch. I presume the OE doesn't have this problem?
 

whitenemesis

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OEM system switches off automatically above approx 10mph

On my W219 the front sensors will go off under braking if the car's been driven 'hard' as the engine heat will set them of, same for reverse. Obviously worse in the cold weather.

Also rain water running off the bonnet can set the fronts off, usually only after initially starting off, depending on the rain intensity.
 

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