Hi, have a clio 2000. has failed its mot because nearside rear fog light does not work and not remidied with new bulb. when brake applied or indicating the fog light on dashboard flickers. please advise.
Many thanks in advance
Hi , have had this one before turned out to be a bad earth in the rear light clusters , light went out on the dash , and fog light worked again. Have a look at the bulb boards in the rear lights , make sure they are clean and no corrosion , especially where the bulbs sit. Make sure of a good earth in both rear light units , Rich:d
Hi , one of the wires going to the rear lights will be the earth , you must make sure this is still got a good ground. If not run an extra peice of wire from the earth on the light cluster, to the shell of the car on both sides , see if this sorts your fault , before you hard wire it all in , This may not work , but it was a fault on one we have done , regards , Rich
THIS IS A FIX FOR THE DIM BRAKE LIGHT/DIRECTION INDICATOR/FOG INDICATOR ISSUE:
First, the fix. Take off the rear light cluster giving problems (hand-removable nut thingy from inside the boot). Might be both, or just one.
Separate the bulb holder bit from the big curvy plastic lens part, might be best to unplug first, from the electrical connector - it's got a springy bit you squeeze as you pull it off.
Now, looking at the column of 4 bulbs facing you on the bulb-holder moulding, note that there is a confusing array of punched metal sheet, with plastic blobs on. Turn the plastic bulb-holder thing over, so the back faces you (where the car's electrical connector went in), and HOLD IT THE 'RIGHT' WAY UP, AS IT WOULD BE ON THE CAR.
There will be a short row of 6 metal 'spikes' sticking out that the electrical connector pushed on to. The third one from the right needs to be twisted through a quarter turn from about halfway down - ie so it sort of gets warped along it's length.
As to WHY this fixes it, it is down to an earthing quirk, I guess that only about 8 volts (out of the 12 volts from the battery) gets 'dropped' across the brake light bulb when you hit the brakes. So, I think in effect, the 'earth' gets raised to a few volts - but not much current is available - and finds a way backwards through something puny which turns out to be the little 21w bulb adjacent to the brake light bulb.
- buy a new rear bulb holder
- pay a garage money to swap out your bulb holder and bulbs
- twist the earth pin as described above, and you might as well do both while you are at it!
Cost my spouse £40 and her mechanic admonished me for trying to initially fix it with an extra earth strap. I wish I had the certainty some people exhibit EVEN WHEN THEY ARE TOTALLY WRONG !!!
Good luck, it's an easy fix this one, you only need a slender pair of pliers to do the twisting/warping of the earth 'pin' with.