Hello everyone i am having to replace the wire harness for the hatchback on my 2012 fiat pop. i have found a 'repair kit' on ebay for this particular problem. just wondering if anyone out there has used one of these kits or did you repair it by using crimped butt connectors on each broken wire? i appreciate all and any suggestions...

I repaired ours using ultra flexible cable one wire at a time without using the kit, took me about 2 1/2 hours and I'm confident at soldering.

thank you!..i spoke with a custom stereo guy and he said i am over thinking, his advice like yours one wire at a time...

Bear in mind that these failures occur because the wires are being repeatedly bent through a sharp angle every time the hatch is opened and closed. It's bad design, and standard automotive cable isn't sufficiently flexible to stand up to the task. So it's not sufficient just patching in standard cable, as it'll soon fail again - you need to use a type of cable that's capable of coping with the repeated bending. The kind that's used for test leads is what you want - it has many more strands than regular cable, and the insulation is designed to cope with the regular flexing.

It's also important to cut the existing cable back at both ends by an inch or two, as the area adjacent to the break will already have been weakened by the work hardening resulting from the regular flexing.

Just reconnecting the ends of the existing wires with a connector won't work.

jrkitching said:

Bear in mind that these failures occur because the wires are being repeatedly bent through a sharp angle every time the hatch is opened and closed. It's bad design, and standard automotive cable isn't sufficiently flexible to stand up to the task. So it's not sufficient just patching in standard cable, as it'll soon fail again - you need to use a type of cable that's capable of coping with the repeated bending. The kind that's used for test leads is what you want - it has many more strands than regular cable, and the insulation is designed to cope with the regular flexing.

It's also important to cut the existing cable back at both ends by an inch or two, as the area adjacent to the break will already have been weakened by the work hardening resulting from the regular flexing.

Just reconnecting the ends of the existing wires with a connector won't work.

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Exactly.

With what I know now, I struggle to believe that fiat weren’t aware that this was an issue on cars...

We run accelerated tests on our cars, to find issues like wiring getting broken through movement like this, chaffing on other components, being cut going across subframes, crushed during assembly etc etc.

We end up lengthening harnesses, shortening them, adding convolute tubing, anti abrasion tape, changing clipping points etc etc

During testing surely would’ve shown this up as an issue...

306maxi said:

During testing surely would’ve shown this up as an issue...

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Probably, but if it will survive until the warranty expires why care?

John202020 said:

Probably, but if it will survive until the warranty expires why care?

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Because operating a sustainable business depends on your customers buying your products more than once.

jrkitching said:

Because operating a sustainable business depends on your customers buying your products more than once.

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That.

I really wish I could share details of my job and the tickets I deal with.

There was one I was dealing with today where one of our cars had done many thousand miles of testing at a test track being mercilessly hammered over rough surfaces and driven through 5 inches of salt water and after it had passed the test with flying colours something broke, even though it passed the test, the failure was still investigated and the part sent back to the supplier for investigation. I doubt any of our customers are going to drive through salt water 5 inches deep well over a thousand times at speed, but it simulates a lifetime of driving in crap conditions because we don’t want customer’s cars breaking down, EVER.

306maxi said:

That.

I really wish I could share details of my job and the tickets I deal with.

There was one I was dealing with today where one of our cars had done many thousand miles of testing at a test track being mercilessly hammered over rough surfaces and driven through 5 inches of salt water and after it had passed the test with flying colours something broke, even though it passed the test, the failure was still investigated and the part sent back to the supplier for investigation. I doubt any of our customers are going to drive through salt water 5 inches deep well over a thousand times at speed, but it simulates a lifetime of driving in crap conditions because we don’t want customer’s cars breaking down, EVER.

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If I had to guess I would say Japanese

Are the repair kits sourced from Germany bog standard auto cable or the better one that you describe?

306maxi said:

There was one I was dealing with today where one of our cars had done many thousand miles of testing at a test track being mercilessly hammered over rough surfaces and driven through 5 inches of salt water and after it had passed the test with flying colours something broke, even though it passed the test, the failure was still investigated and the part sent back to the supplier for investigation. I doubt any of our customers are going to drive through salt water 5 inches deep well over a thousand times at speed, but it simulates a lifetime of driving in crap conditions because we don’t want customer’s cars breaking down, EVER.

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If only Fiat would take this attitude on board.

Another good example of what not to do is the HVAC flap actuator mechanism on climate equipped 500's/Pandas. Yesterday saw yet another failure thread for this all too common fault. If you're going to bury parts deep into the interior where subsequent access is going to require 10+ hrs skilled labour to access, you don't make them out of flimsy plastic that's only just able to handle the stresses of routine operation when new; you engineer them to outlast the car in 99.999% of cases.

You then don't compound this mistake by supplying the failed component (which costs only pennies to make) only as part of a complete assembly costing many hundreds of pounds.

For anyone wanting to buy a long term keeper with climate, this issue alone is sufficiently serious to strike Fiat straight off the longlist of possible marques.

typecastboy said:

Are the repair kits sourced from Germany bog standard auto cable or the better one that you describe?

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By now there may be more than one aftermarket supplier for these - the failure is common enough .

I've not seen one so can't comment properly, but the (translated) description in this ebay listing suggests this one might be.

"You purchase a cable repair kit from an ultralight silicone cable to in future to prevent a further breakage."

306maxi said:

During testing surely would’ve shown this up as an issue...

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Putting fiats “that’ll do” attitude aside, I think there are two things going on here.

1. is the repetitive movement putting stress on the harness, that can be tested for easily as I’m sure you know.

2. Is the material the insulation is made out of, many years back Mercedes changed the material they used on wiring insulation to a type that would biodegrade, however it started biodegrading in the cars long before it was supposed to, I don’t believe this is to quite the same level as Mercedes, but the repetitive movement, age, cold and heat all combining creates this problem.

On a bench flexing the wires back and forth wouldn’t necessarily replicate the fault, but take 6-10 years of roasting hot summers, freezing winters, exposure to the elements and being continually flexed, is what is causing the insulation to fail. Once the insulation breaks down the copper is less supported and more likely to fracture.

It’s interested that it is predominantly the hatch wiring which is high up on the car so likely to get the brunt of the sun in the summer months and be exposed to ice in the winter.

You could argue the drivers door is used many many more times but there don’t seem to be the same problems there, my theory is because the wiring to the door is better protected from extremes of hot and cold

AndyRKett said:

You could argue the drivers door is used many many more times but there don’t seem to be the same problems there, my theory is because the wiring to the door is better protected from extremes of hot and cold

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The primary reason the hatch wiring fails is because the design means that a small section of the harness is bent through a sharp angle, and the materials chosen can't cope with the repeated flexing. With the door wiring, the bending is distributed across a longer section of the harness, and the angle through which it is bent is smaller. It's peculiar to the 500; the Panda, with similar wiring in a similar position, doesn't suffer this problem, which points the finger quite clearly at the specifics of the 500 design.

That said, extremes of temperature (primarily cold, which makes both the conductor and the insulation more brittle) will likely exacerbate the problem and cause failure to occur earlier; it's possible that testing during the Italian summer might not show up a problem that is more likely to occur in an English winter, but you'd expect any car manufacturer to do both cold soak and hot soak tests before releasing the design to production.

Avoiding using the hatch when temperatures are below freezing may well prolong the life of the wiring, but most will fail eventually.

AndyRKett said:

Once the insulation breaks down the copper is less supported and more likely to fracture.

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Yes; all the ones I've examined closely look as if the insulation failed before the conductor. So any repair needs to be done with wire that has better resistance to repetitive bending, hence the use of silicone insulated cables in some of the aftermarket repair kits. Having more, but thinner, strands in the conductor is also highly desirable; I'd want to use at least a 35 strand conductor silicone insulated cable for any repair in this area.

I don’t think heat is a factor tbh. As jrkitching says, its the angle of movement that’s the issue. I will have to take a video of mine and you’ll see what I mean. My 3 series is completely different in the way the wire is bending when the hatch is open.

From memory the 500’s harness exits the body and bends and then it’s the bent bit that also gets twisted by the movement of the hatch. This is a major stress point. I rather suspect that to make it 100% reliable would have required a change to a pressed body part which is tens/hundreds of thousands of pounds of cost in tooling.

306maxi said:

From memory the 500’s harness exits the body and bends and then it’s the bent bit that also gets twisted by the movement of the hatch. This is a major stress point. I rather suspect that to make it 100% reliable would have required a change to a pressed body part which is tens/hundreds of thousands of pounds of cost in tooling.

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:yeahthat:



I'd forgotten about the twisting; it's the combination of repetitive bending and torsional stresses on the cable that precipitates early failure. The door wiring only has to bend - there's no twisting involved.

And you're right; fixing this properly would require a fundamental change to the way the wiring routes through the hatch and this would not be cheap. It's a shame; the Panda doesn't have this problem, which just goes to show that whenever you make even a relatively small change to a design that works, there's always the risk of introducing a new problem that wasn't there before.

The Panda door handles are another example; they may not be as pretty as the 500 design, but they do generally stay attached to the car for the whole of its natuiral life.

Reengineering the Panda 169 into the 500 really is a triumph of form over function. I guess that's what sells cars in the short term, but I know which one of the two I'd buy again.

I would look at replacing the cables with a good quality silicone wire with a high strand count, ultra flexible and durable. Can be picked up online by the metre relatively cheap.

the repair kit i found on ebay is made in germany

birdy2005 said:

the repair kit i found on ebay is made in germany

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Most of them seem to be made there, though they don't state what type of cable is used, but it will fix it and may work for the rest of the time you have the car?