7 replies to this topic

[Riffy]

Thought the bulb had gone in my driver's side headlight (dipped/full beam) so replaced with the relevant H4 bulb.

However this made no difference at all...so...checked the relevant fuses for the headlights and they appear in order (viewed them - no breaks etc... in them).

Then noted that both numberplate bulbs were out. Checked and they were totally corroded and falling apart so fear i will need to replace the whole lighting units, connectors etc...

Could the numberplate lights being out influence the headlight problem???? Sidelights working fine, just full beam and dipped headlight that wont work driver's side only. ALL other lights fine bar numberplate ones as stated...

This is really annoying me with no night driving!!

Thanks for any help

[Mondy55]

Had a similar problem with my Mk1 Focus - though my problem was down to the fact that I managed to get a single-element bulb in where a stop/tail light bulb should go, which inadvertently connected the stop/tail circuits together and popped some fuses. The upshot was no rear lights on one side, and no number plate lights. I had ST170 headlights on at the time with separate h1/h7s and I'm sure there was some issue there as well (this was probably 4 or 5 years back).

You might want to check you don't have a bad earth somewhere too, as well as making a few investigations as to why the bulb holders have rusted up so badly (my money would be on rust behind the boot handle).

[Riffy]

Just confused as to why headlight electrics would suddenly just not work? Headlight was working fine a week ago.

Bought some new number plate bulbs, popped the light fittings out tonight and water literally poured out!!

Maybe i should pay some Ford Dealership about £800 to sort this sh1t out. So cheesed off.

[GazSi]

Headlight wireing might be corroded mate, the numberplate lights are an easy fix mate

[Riffy]

Is there a fuse for the number plate lights? Cant see one indicated in my Haynes manual???? Have bought some new numberplate light fittings some hopefully i can just chop the existing wires and splice in my new ones?!!!!

Have checked earth for headlight and all appears in order. Have removed driver's side headlight and wiring appears non-corroded. Have tried to follow wiring as far as i could but too many wires and too little knowledge on my part!!! Am guessing that there is a break in the wire somewhere between headlight and fuse box.... unsure how this could have come about though...

Is there a way that i could splice a wire directly from the working headlight across to the faulty one??? This would be much easier than trying to replace whole wiring between fusebox and driver's headlight. FFS, stupid electrics.

[Oz]

Yes, you could - using a relay to flick the other lamp on. That way all the current for both lamps isn't being drawn from one side's wiring. Have you got a voltmeter, and can you test the wires for continuity?

[Rincewind87]

Or you could fix the broken earth, it's the only common for the h4 bulb

[Riffy]

This is still ongoing...

Replaced my number plate fittings, spliced in the wires etc and that worked a treat so that side is sorted.

Just the headlight to sort out...

Have swapped everything around.... fuses, relays, etc... and still no joy.

Took both headlights out and swapped them around, lo and behold the passenger side when connected to the driver's side doesnt work. Obviously therefore i figured it must be a problem with the wiring to the driver's side.

Ref possible bad earth...i have run a wire from the + battery terminal to the actual physical light fitting of the headlight bulb and this causes it to illuminate... i presume therefore that it is properly earthed????

I have a small light up circuit tester device and i have linked this to the + battery terminal and then touched the other end on the physical light fitting of the headlight bulb and this shows power on all 3 fitting points that the bulb touches...surely this means that there is power running through the fitting/headlight and that it should be lighting up....???

I also have tested the power plug which supplies power to the headlight unit, and this appears to be powered...also the sidelight is working so there must be power coming into the unit...

I was thinking that there must be a bad wire from the fusebox to the headlight however the fact that there is power to the actual headlight fitting suggests that this is not the case????

What is my next port of call....? As you can tell i have little experience of car electrics, however i am convinced it must be something relatively simple as i have ruled so many things out...

I have also tested power at the fusebox and get my little light coming on at these points so there is power running through the fuse points...

It is really frustrating me and i know i will probably end up paying someone to sort this but i would really like to sort out myself...!!

I do not have a multimeter/voltmeter - would this help me? I have read about testing the continuity of wires...would this help and how do i do it?

Many questions and babbling i know. Thanks though...