Punto (Mk2/2b) The Basics of the Bulb Malfunction Light

Following the rear bulb replacement section, get the affected light cluster out the car
With the electrical connection removed, do 2 things
Locate your black wire, this is the EARTHING wire, but look at the connection inside


My connecter is looking a little loose on the black wire, the gaps a tiny bit bigger
You may be able to make the gap smaller to ensure a tight connection again, but mostly its the cluster at fault

So where the black wire connects - locate that pin

Mine in this example is the far Left pin

Is it dull, black, missing, white, furry, covered in plastic, brown or anything that isn't as shown in picture?
Clean it up, Both sides
Sand paper, wire wool, a small needle file, anything to remove the corrosion or defectant thats causing a resistive path, till its shiny and clean
Solvent cleaner might work, but i've had little success personally

So its now clean and looking much better
Great, refit connector and test away
And you should now be fault free!

If 1 cluster has faltered with an earthing fault, the other side may be at fault too
so while your out doing this - tackle the other side

People who have the Fiat 100W subwoofer in the boot, you will need to remove the subwoofer to gain access to bottom stud nut