Citroen C3 Multiple Bulb Out Warning Fix

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GiveMeABreak
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Citroen C3 Multiple Bulb Out Warning Fix

Post by GiveMeABreak » 01 May 2019, 12:09

If you have a C3 to circa 2009 and are getting random bulb out failure warnings on the central display - some examples:

"Info LH Rear Brake Faulty"
"Info LH Rear Fog Faulty"
"Info LH Rear Indicator Faulty"

If you get these warnings randomly then you probably have a the common issue with the earth wire pin in the rear lamp cluster (s). Mine was on the rear left, but can be the right - so check both.

Basically the earth wire acts as the earth to all the lights on the rear cluster and is insufficient to cope with the load.
  • It's easy to remove the rear cluster - for the left hand side, in the boot, there is a small plastic cover on the plastic trim that can be pulled away.
  • Next, reach in and unplug the wiring plug.
  • From there use a 10mm socket to locate and unscrew the bolt - but be careful to catch it!
  • The other nut is on the outside of the lamp cluster.
  • Carefully ease out the unit - there are a couple of plastic guide poles so be careful not to break these as you pull the assembly toward you.
C3 A.png
C3 B.png
This is a picture of the right hand plug;
as you can see, it looks pretty normal.
Compare this to the left hand side;
You can see the earth pin is completely melted away!
Fix
So the solution is either to purchase a new plug and faff about reinserting the pins and wiring - (which won't cure the problem anyway) - or bypass the earth from the plug and wire directly to the earth plate of the light circuit.

If following my solution, make sure you do all the work on the cluster end first.
  • Drill a small hole through the assembly plastic
  • Drill another hole through the metal earth plate as shown below.
  • Make sure the drill hole in the plastic is smoothed with no sharp /rough edges, so as not to cut the wire sleeve.
  • Wire an electrical connector to the earth and seal with heat shrink wrap (in yellow below).
  • Use a small self-tapping screw to secure the earth to the metal plate. Be careful to position this correctly and do not use too big a screw or you will not be able to fit the bulb.
  • Now you need to splice into the existing earth wire that feeds the plug.
  • Cut the earth wire at the plug.
  • Before making your connection, make sure you allow sufficient length of wire to allow the light cluster to be removed (and for working on) for bulb changing at a later date!
  • Splice into the earth wire and join your new earth using a suitable connector. I sealed with heat shrink to ensure good insulation.
Carefully tuck the wire into the assembly after fitting the bulb and re-fit the assembly, making sure not to over-tighten the bolts.
C3 C.png