[Mandalou40]

Could anyone give me some advice please? Driven car home from work today (307, 2005 1.6 diesel) when I stopped I could smell a burning plastic type smell but not strong and couldn't figure out where from. Saw rear drivers side indicator light was on solid after key out of ignition. Was so hot and only way I could turn it off was disconnect light cluster.

I'm a woman on my own with 2 kids and although I'm quite savvy with cars (dad was a great teacher) cannot figure out why. Took cluster out and bulb blown and melted plastic casing was obviously what I could smell as light must have been on for some time. Replaced bulb and cleared broken glass.

Is it likely to be an expensive job?

 

[WillNZ]

Is there any damage to the wiring and plug? Particularly the terminals inside the plug? If the connection between the pins in the light and the contacts in the plug is not good, it needs to be sorted out.

I would try to plug the passenger side's bulb cluster into the driver's side plug and see if the indicator still lights up without being activated.

If it does, check if the other bulbs on the driver's side indicator circuit are also on. [front and side repeater]. If they are, then have a look at the comms unit [indicator/light stalk unit]. If not, then check the wiring into the car is not damaged/shorting in the boot/further inside somewhere.

Hopefully it is just a bad driver's side bulb cluster..

 

[Mandalou40]

Just been and looked again, passenger side had indicator wire soldered directly to cluster! Weird! It came off so no longer have indicator on that side ? However...bulb no longer staying on on drivers side but no longer working at all (front & sides are fine) lights on assembler side rear no longer working now! I give up, I'm assuming it's a wiring problem

 

[TobMo1]

I had that problem with a old Peugeot!

And I was advised to buy the parts I needed from Eurocarparts.com

Open an account....they are cheap as chips and very helpful, reliable and trustworthy,

 

[WillNZ]

The 407's have a problem with the rear lights, the contacts between the plug and cluster are inadequate and they burn the ground contact away. The solution is to wire the cluster directly to the plug wire. I have had to do this for both my 407's in both rear light clusters, and there are plenty of threads on this issue.
It sounds like your issue is similar given the bypass wire you found. Probably wiring the bulb cluster directly to the loom, or replacing the existing plug with a more sturdy plug or crimp on male/female connectors will sort your issue out.