C3 Dim And Then No Headlamps

[truckdoctor2004]

Hi

Could someone help please

Our C3 has developed a fault with the dipped beam headlights, they have been getting dimmer over the last few weeks and finaly last night they failed to light up at all. Checking the fuses i found them to be OK, not sure if there is a cetral earth point for both lamps and wonder if there is a wiring diagram available,

Has any one found something similar ?The bulbs semm to be OK

Help please

[credowan]

Hi, having a quick look through the haynes manual just to make sure fuses to have checked are (Engine fuse box) F9 LH dipped, F10 RH dipped both 15A fuses

 

Looking at the earthing points each headlight have a seperate earth E9 Behind left hand headlight,E14 RH engine compartment it seems the bulb is earthed off the headlight therefore needs to be in the postion to create the circuit? could be wrong sure someone more exsperience will be a long to confirm

 

You could possibly check the bulb condition with a mulitimeter if you`ve got one, try not to touch the bulb glass itself as it can make it prematurely blow

 

hope this may help

Gary

[truckdoctor2004]

Hi, having a quick look through the haynes manual just to make sure fuses to have checked are (Engine fuse box) F9 LH dipped, F10 RH dipped both 15A fuses

 

Looking at the earthing points each headlight have a seperate earth E9 Behind left hand headlight,E14 RH engine compartment it seems the bulb is earthed off the headlight therefore needs to be in the postion to create the circuit? could be wrong sure someone more exsperience will be a long to confirm

 

You could possibly check the bulb condition with a mulitimeter if you`ve got one, try not to touch the bulb glass itself as it can make it prematurely blow

 

hope this may help

Gary

[truckdoctor2004]

Thanks Gary, Yes i have multimeter and the bulbs are fine ,interesting they have seperate earthing points, i cant see that both earthing points would go bad at the same time.

I wonder if there is a relay that supplies the two 15 amp fuses you mentioned. As i have no diagram ,could you check this for me please. By the way it is an 05 reg.car

Thanks Steve

[paul.h]

I have a wiring diagram in the RTA manual for the petrol cars but not sure if it covers all years. The circuit shows a supply from the battery in to the under bonnet fusebox which appears to go to a double relay which feeds the main beams and also the dip beams. A signal from the BSI pulls in the relay for main and another signal the relay for dip. From the double relay each outlet splits so all 4 beams have their separate fuses and the wires then go to the lights. The fusebox has an earth for everything in it.

 

So my first guess would be a relay fault - see if it is installed properly and the connections are clean but it may need replacing. It may be buzzing if internals are not giving a good contact. Check for a 12 volt supply out of the relay at each fuse with the lights switched on. With the relay out you could check for 12 volts where it plugs in. Also try a supply direct from the battery to one of the fuses to by-pass the relay and both lights should work. Do the main beams work ok ? As noted above, each front light unit has its own earth but this is common to all lamps in each unit.