Technical Fiat 500 Number plate lights not working

[Bianco]

Hi all,
You may remember around November last year the number plate lights on our 500 stopped working but the tailgate lock still worked ok?
Well, over Christmas they behaved themselves up until mid January when the warning light appeared again on the dashboard.
We put it into Fiats for a service and asked for the problem to be sorted.
We were told it needed a new number plate light/ release switch assembly at around £120 but they didn't have one in stock.
Now the weather is warming up a bit, I decided to have a look myself. I had voltage at the unit connector of 12 volts for the switch but only 4 volts for the lights.
I removed the assembly from the car and applied a 12 volt source to the connector, which worked!
As the switch was ok, that meant the ground was good so I just put a slight kink in the live feed finger inside the connector for the light and it's now working!
Why the low volt reading earlier? It could be that modern practice is to put computers in vehicles and if there's a problem, it could be a way of the BCM protecting itself from overload possibly? I don't know as I'm old school with, battery, wire, switch, bulb - works!
Anyway, if you're going to try this fix remember only to put a slight kink in the finger not a bend, that would probably break the connector anyway!
Good luck.

 

[Srhutch]

Hi all,
You may remember around November last year the number plate lights on our 500 stopped working but the tailgate lock still worked ok?
Well, over Christmas they behaved themselves up until mid January when the warning light appeared again on the dashboard.
We put it into Fiats for a service and asked for the problem to be sorted.
We were told it needed a new number plate light/ release switch assembly at around £120 but they didn't have one in stock.
Now the weather is warming up a bit, I decided to have a look myself. I had voltage at the unit connector of 12 volts for the switch but only 4 volts for the lights.
I removed the assembly from the car and applied a 12 volt source to the connector, which worked!
As the switch was ok, that meant the ground was good so I just put a slight kink in the live feed finger inside the connector for the light and it's now working!
Why the low volt reading earlier? It could be that modern practice is to put computers in vehicles and if there's a problem, it could be a way of the BCM protecting itself from overload possibly? I don't know as I'm old school with, battery, wire, switch, bulb - works!
Anyway, if you're going to try this fix remember only to put a slight kink in the finger not a bend, that would probably break the connector anyway!
Good luck.

Thanks for the connector bend tip. I had 6volts at the plug and continuity of the light circuit but no lights. Slight bend of the light board plug connectors and bingo all working.

 

[Bianco]

Great stuff Srhutch.
It just annoys me so much these days as to the quality of auto components. They are just not fit for purpose. In my day it was bullet connectors which gave a rock-solid electrical connection and no problems. The modern connectors are cleverly designed to either break when disconnected or fail, as in our case due to flimsy construction. Touch wood, our lights are still working OK now.

 

[Srhutch]

Great stuff Srhutch.
It just annoys me so much these days as to the quality of auto components. They are just not fit for purpose. In my day it was bullet connectors which gave a rock-solid electrical connection and no problems. The modern connectors are cleverly designed to either break when disconnected or fail, as in our case due to flimsy construction. Touch wood, our lights are still working OK now.

Well I fixed it half an hour before the MOT as until last night they had been working. Passed today so I don’t have to worry for a year ;-)

 

[Bianco]

Hello all (again).
Guess what? Yep, during the recent cold damp spell, that yellow warning light on the dashboard showed its face again with the,' number plate light not working' warning. Of course I checked the connector first and that was good and tight. So removing the unit again and putting the terminals across a battery - nothing! I pulled the light/tailgate lock unit apart to find a rubber gasket in the way of progress. This was carefully peeled back halfway along the unit (from the connector end) using a hairdryer and craft knife. Heat the gasket to soften the adhesive then slice between the plastic moulding and the underside of the gasket with the knife. Work slowly and all will be revealed! Note: I could have just sliced into the gasket to reveal the lamp holder but seeing all the muck washed down between the back of the light unit and the tailgate - if any water got into that plastic section, it would just sit there and cause more problems. Anyway, after managing to get to a point I could access the lamp holder, I stopped peeling the gasket and unclipped the lamp holder (4 clips).
This is what I found:

From the photo you can see, The hairdryer (sorry about that!) The part peeled gasket and the grey festoon lamp holder. Now able to access this quickly highlighted the fault. The red positive wires to the terminal end of the lamp holder had good continuity. The ground/earth wires black & black with brown tracer were very high (over 100 Ohms) and giving an unstable reading. Both readings taken from the main connector to the terminal ends.

Here I'm removing the ground attachment to the terminal. I heated the plastic blob locking it in place with a small (18watt) soldering iron and levered it out with a small screwdriver. You can also see the crocodile clip from a 'Helping Hands' that is very useful during this operation. As it came apart, you could see the difference between the two wires. One had been half-stripped and the other, not stripped at all and just relying on the tapered slot to penetrate the insulation - probably a Friday afternoon job at the factory?

I now swung that end of the terminal plate clear and stripped the ends of both cables. I tinned the end of the wires but couldn't get a good fit in the terminal. In the end I went for a 'Belt & Braces' job answer, and bent up that centre finger at the cable end of the terminal plate, tinned it and soldered the two ground wires onto that - see below.

I finished off by squeezing it back into the plastic moulding with the tip of the soldering iron and it held ok. Clipped the lamp holder back into the main assembly, inserted a lamp and connected the battery - all worked well, so I then carefully re-laid the gasket.
Before bolting the unit back on the car, I plugged in the connector and checked the operation of the lock release and the lights - all were fine so I'm now confident I've finally cracked it!
It's the cheap, poor quality of parts that's the problem.

 

[steveras57]

And Mario,s wine soaked Friday afternoon assembly! good fix and well done for posting up such a detailed guide to the fix for others who have a similar problem.

 

[GettinBetter]

Oxidization, a real circuit killer. Just a microscopic layer of oxide build up will render most circuits inoperable. I usually copper grease them up before assembly. I also if possible (depending on plug and socket type) tweak the clamping portion of the connector to make it a tighter fit.

 

[Piccolo Nero e Bella]

Your 'orrible climate strikes again! I fitted LED replacements several years ago but they still use dummy bulbs in the festoon mounts so it's useful to know this fix.

 

[steveras57]

Your 'orrible climate strikes again! I fitted LED replacements several years ago but they still use dummy bulbs in the festoon mounts so it's useful to know this fix.

Well if climate change is gonna happen i for one hope it works like the magnetic poles reversing every few millennia and we up here end up roasting whilst you sit down there shivering into yer wellies for a change!

 

[Piccolo Nero e Bella]

Well if climate change is gonna happen i for one hope it works like the magnetic poles reversing every few millennia and we up here end up roasting whilst you sit down there shivering into yer wellies for a change!

And you can have the spiders...

Scientists discover bigger, more venomous species of deadly funnel-web spider, nicknamed "Big Boys"

The deadly 3.54-inch-long spider Atrax christenseni is among the most dangerously venomous spiders for humans.

www.cbsnews.com

 

[steveras57]

And you can have the spiders...

Scientists discover bigger, more venomous species of deadly funnel-web spider, nicknamed "Big Boys"

The deadly 3.54-inch-long spider Atrax christenseni is among the most dangerously venomous spiders for humans.

www.cbsnews.com

Spiders i can stamp on! low pressure systems not so much!