BryzeMo

Number Plate Bulb Issues (No Power)

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Hi folks. Im new to your forum and require some help. I currently drive a 2007 ford fiesta zetec s.

Ok.....was driving at night the other day when i was flashed over by another car. He told me i had no brake lights except for the strip under the roof spoiler. So i went and got new bulbs which fix this problem. Happy days!

However now both my number plate lights no longer work. I hav been out all day trying to find the reason why, where i have replaced both bulbs, checked the fuse and even replaced some corroded connectors. But still nothing. I then put my multimeter on and there is no power at the bulb connectors i also checked for continunity between both connectors and all good. I did notice when i was replacing the connectors that some of the copper wire strands were blackened (not sure if this tells you anything or not) I have been looking at other threads and cant seem to find a solution and just wondered if anyone has had a similar problem. Any advise would be great as im at a lose.

Thanks Bryan

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The black on the wires is oxidation usually caused by condensation.

Cut back to clean copper and crimp/solder in some new cable to restore length as necessary.

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Hi

My electrical troubles continue!! I havent had a chance to follow Stoneys advise above yet on the number plate bulbs but was driving the car tonight and i now hav no intrument cluster lights on my speedo, rev counter, heater knobs etc?? I know these are all linked by the same fuse but checked this 7.5a fuse and is ok. Any ideas whats going on here?

Thanks

Bryan

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check the wires as they enter the tailgate, common to see breakages here

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Thanks Wase. Will have a look in that area also. Would u happen to know why my instrument cluster no longer lights up? Are there any other fuses i should be aware of? Thx

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just had a quick look at the wiring diagram

fuse 33, 7.5a seems to be the fuse, so check thats the one you've looked at

also see that there is a direct link between number plate lamps and instrument lights, they are joined to the same wire from fuse 33 to multifunction control module, though doesnt show where that join is..

so i would concentrate on the number plate lamps first, as this may sort the instrument lights too..

if it was me, first place i would check is where the loom enters the tailgate, peel back the rubber sleeve and check all the wires, common to find complete breakages and/or splits in insulation which can cause shorting across each other

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+1.

The flexi joint between the roof and boot takes a lot of punishment and broken wires are very common.

The insulation gets hard and brittle which basically chops the wire cores.

A bit of damp across the bared cores will short across and blow fuses very quickly.

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Ok thats for all the advise n pointers guys. Really helpful this will be my job for this weekend due to busy work n family life. Will keep u guys posted with my findings n hopefully fixes.

Thanks

Bryan

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Hi guys. Well i hav spent all today trying to fix this problem with no joy.

I started at the boot hinge and all cables were fine. I hav changed all connectors and the black oxidised cables. I also started to trace the cables back to the fuses box were continunity was good throughout. I also found the join where it branches of into two cable one to the module and the other to the fuse box. When i checked this for power, one probe in the fuse and the other at the join im getting 12v? However when i check power from here back to the number plate bulbs nothing?? But i get continunity. I have played/wiggled with all the cables while the car is running n still no sign of a flicker of power to the bulbs. Any ideas guys?

There is also a reley above the fuses which i can hear ticking when car is on but stops after a couple of mins when car is off??

Many Thanks

Bryan

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if ive read this right, you shouldnt have 12v if connecting probes to fuse and connection where it filters off to multifunction module.

this indicates you have a live feed and earth on a wire that should be live at both connections

with sidelights on, negative probe attatched to an earth, you should have 12v at fuse 33, 12v at the connection,

wire diagram shows switch feeds to fuse, which then heads off to a splice, one to mutifunction, one to bulb holder, looks like it feeds the left hand no plate bulb which then bridges across to right hand no plate bulb

you possibly have 2 further splices on this wire, one between the fuse and mutifunction splice, which heads to hazard warning switch, shoulfd think this is for the switch illumination.

the other is spliced between the mutifunction splice and the multifunction module, this further splice heads to the 'sidelight on' warning bulb in instrument panel.

all of these connection should read 12v when you have the negative probe connected to an earth...

so, initial question, is the sidelights on illuminating on instrument panel?

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Hi wase. First off thanks for your input and you time.

The question u hav asked im assuming is when u turn on the lights there is a little light symbol on the intrument panel which i believe is green to let the driver know his lights are on. The is NOT coming on when i turn on my lights.

Thanks

Bryan

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are you aware if this used to work before?

(may also be worth checking to see if hazard light switch illuminates with sidelights on)

if i take it that it did, then first port of call has to be confirming you have 12v both sides of the fuse with sidelights on, then testing the connection you found previously that splices towards the multifunction..

its starting to sound like a fusebox internal connection, if im right then you wont have 12v at the multifunction splice

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Yes this green light did work before and as for the hazard switch i cant recall if this illuminates or not.

I was thinking of purchasing a haynes manual for my car would this be worth getting?

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up to you, its quite a basic circuit which wont give you much more (if any) info that ive given.

you stated you ran a continuity test, can i ask where you confirmed the continuity was good...ie, did you test between lamp and that multifunction spliced connection, or did you go further back to the fuse?

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The cables from the number plate connection run down as far as a multi connecter just beside the rear seatbelt anchor - I checked continunity between and all good.

The cables then run from the female end of that multi connector down and along the floor of the car to that splice which is near the bonnet latch on the passengers side - checked continunity here and all good.

Thinking about it i didnt check for continunity as a fully connected circuit.

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can you confirm if you definitely have 12v at fuse 33 with sidelights on...

1- if you have then need to find wire as it leaves fusebox and test for 12v...

2- if you havent then need to test for 12v from switch..

for further info

wire from switch to fuse is orange/blue

from fuse to lamps orange/black

from splice to hazard is orange/green

from splice to multifunction is orange/black

splice on mutifunction to sidelight on indicator is orange/blue

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Hi Wase. I have just checked the fuse with side lights on and connected to an earth and getting 12v. I hav disassembled the switch unit and i get 12v with side lights on.

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You should only be getting 12v from one side

If you put one of your probes on a door hinge or a bare piece of metal and then put your other lead in one side of the fuse holder then you should get 12v on one side only

Imagine there is 12v upto the fuse (from the battery) and the fuse allows that power to flow through and go to the bulb

Not sure if that makes it any clearer or not

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Yeah that's how it should be

Without a wiring diagram, I would assume that it is a continuous wire from the fuse box to the light bulb holder

Would be abit difficult to test, but if you put one of your probes on the side of the fuse holder with no voltage, and the other one in the bulb holder (you would have to try both sides of it) with your multimeter set to either ohms or continuity

You should be able to see if there is a break in the wiring between the fuse box and the bulb holder

(As I say without a wiring diagram I can't be certain there is nothing between it, but I assume this would give you the correct answer)

You could also check to see if there is continuity between one side of the bulb holders and an earthing point on the car (just to make sure that there is a good earth on the bulb holder)

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I guess i now need to check the wire as it leaves the back of the fuse box which i think travels down to the multi connector. I have finished for tonight as im loosing daylight but thanks for the help and until tomorrow my electrical problem continues! Anymore advice is truely welcome! Thanks guys.

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