General Fiat 500 tailgate wiring - fixed!

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General Fiat 500 tailgate wiring - fixed!

Burgerbob

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Hi All - I appreciate that this has been covered before but having fixed my daughter's car this morning I thought I would share this as I suspect many other people will have similar issues.

My daughter has had her 2008 Fiat 500 for a couple of years now. The demister has never worked, just blowing fuses, there has been issues with the number plate lights and I'm pretty sure at one time the rear windscreen wiper was controlled by the demister switch. Anyway, a couple of weeks ago a fuse blew, after shutting the boot, and the speedo stopped working. She got really upset and I thought it was time we did something about it.

We had traced the fault to the wiring loom where it enters the boot - a common issue for the 500

So we bought this repair kit made by Vemo.

https://www.onlinecarparts.co.uk/vemo-875647.html

And followed this guide (albeit it is for a different car, but same principal).



I cut out the original rubber wire harness between the cars body and the tailgate to reveal the wires. I was a little shocked by what I saw so I took the attached photo. There are 14 wires in total plus the tube for the washer. Every wire had split its insulation revealing the bare wire. Two wires had broken right through. No wonder the electrics were playing up.

The Vemo repair kit was surprisingly of a higher quality that I expected and I would recommended. The wires are very flexible (and contain multiple very fine stranded wire) which highlights the issue. Fiat has fitted very un-flexible wire in a area that needs to flex each time the boot is shut. I'm not at all surprised the wires have all broken. The kit actually had 15 wires, I'm guessing in case there is a reversing camera fitted.

The repair kit is fitted with bullet crimping connectors, again these are of a decent quality.

To fit, you need to be brave and cut all the wires in the car, chop out the broken section and then crimp on the repair kit. I took my time as it is not hard, but there is not a lot of room for wire strippes and the crimping tool. I also took of the trim from the back of the boot lid. This allowed me to free up the wiring loom and pull more through to get a bit more space.

All the fiat wires are colour coded as is the repair kit, but not with the same colours. So take your time and crimp one wire at a time so you don't get them mixed up.

Once done, its just a matter of pushing the wires and crimps back into the body of the car, and tailgate. Refitting the trim on the boot and pushing the rubber harness into place.

It's a fiddly job, but not hard. I found it easier with my cheap basic crimping tool and wire stripper rather than my more fancy (but still cheap) ratchet ones. The ratchet ones are more bulky and I couldn't get them into the space.

Anyway, if you are suffering electrical problems, hopefully this may give an idea of how it can be fixed.

Rob
 

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Very useful post, Bob. Out of interest, is the wire in the repair kit more flexible than the original wire?
 
Bob, that is absolutely brilliant. I am this week dealing with the same issue. I have posted my problem and was pointed to your post.

https://www.fiatforum.com/500/471909-rear-brake-problem-big-one.html

A small point. You mention your basic tools a crimper and wire stripper. I presently don’t have either so would appreciate a photo of yours as you mention size is important! ;)
Thank you.
 
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Very useful post, Bob. Out of interest, is the wire in the repair kit more flexible than the original wire?

Yes - the wire in the repair kit is massively more flexible that the wiring in the loom. It's made up of multiple very fine strands of wire, compared to much thicker strands of wire in the loom.

Comparing the two, it was no surprise that the fiat loom broke.
 
You mention your basic tools a crimper and wire stripper. I presently don’t have either so would appreciate a photo of yours as you mention size is important! ;)
Thank you.

Many thanks

Knowing I had to do plenty of stripping and crimping I used the excuse to buy myself better quality tools.

On the right in the picture you can see my new ratchet crimping tool and strippers. I'm sure these are very good, but too bulky to use in the space. My old cheap ones on the left worked fine, it was still a little fiddly but manageable.

Removing the trim from the boot and pulling the wire through to get more space was vital. It may be possible to strip down the trim at the back of the car to free up the wiring loom from the car side, but I managed without doing this.

The kit comes with two pieces of heat shrink, I couldn't figure out what these were for at the time but it dawned on my afterwards. You have to cut and rejoin the tube for the rear washer. The heat shrink is to put over the join to seal it. I just used some duct tape and it was fine.

Hope it goes well!
 

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Bob, great recommendation and picture. I've repaired the loom twice now in 11 years by putting in short replacement sections on the affected wires with hear shrink for protection. I think the next time will be a proper repair using the VEMO kit.
 
Just wanted to follow up and thank everyone for this informative post, my wifes car had the same issue transpire and i hadn't even noticed the number plate lights not working just the failure of the tailgate to operate from the button. Read the post and found the suggested repair and bit the bullet and ordered a sencon repair kit from Amazon for £22 plus i paid an extra £4.99 for next day delivery. Great bit of kit but scary as hell looking at how many wires are involved.
The kit arrived and i ventured out and began to gain access as bob suggested as with others kits no instructions included but once i realised the colours didn't need to match on the new section as long as they matched the rejoined section (obvious really) then everything fell into place.
Getting the cable harness pulled through took a bit of work but cutting off the gaitor and the proted wrap was fiddly as i didn't want to cut any of the wires with the blade, when i got it off i too was shocked by the sight of both the cut wires but also the bare exposed wires.
I had an old wire crimping set in my shed that i had never used but it worked a treat although it is very fiddly but doing one wire at a time is best. I made one mistake getting too confident towards the end and actually snipped the connector in half with the cutter instead of the crimper but luckily there is a spare wire in the harness which i recut and used instead. I added plumbers ptfe tape to the water pipe and also used the heat shrink and a hairdryer to seal.
One all the wires are connected getting them back inti the roof and tailgate takes a lot of poking and prodding but it does eventually go in and then its a case ot trying to get the grommets to fit in place. Once everything was back together i refitted the negative battery terminal and tested the number plate lights were working they were so i was pleased, then i pressed the boot opening button on the car and nothing happened. I was gutted and sure i had maybe snagged one of the wires etc etc so i locked all the doors again and tried again and this time everything worked perfectly i think the car had to do some sort of system reset and it now works perfectly. Thanks for the help and here is a couple of pictures to show what mine looked like. Hope it helps someone else.
 

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The foto of the chafed wiring looks very familiar. I pulled the trim from the C pillar and the hatch so i could pull the extra wiring in instead of pushing it.

gr J
Yes i managed to get the inside trim off most of the way as i also did with the hatchback trim mostly in order to try and help wrestle the wiring back in, it does seem a lot of bits to try and get back in though.
 
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