hi all, i recently got stopped by police for having none of my rear sidelights working (no ticket, very nice guy). i cannot for the life of me figure out why they don't work though. i've tried new bulbs, checked all the fuses (by eye), and had a look at the earth connection too (seems ok). i've been told there's a relay (canbus i think it was called) that could be the fault? any other ideas, or help would be appreciated, thanks. 

More likely to be the switch unit, they are known to fail, however you can test the circuit by leaving the indicator on and switching the ignition off, one of your side lights should remain lit.

Have you definitely changed the correct bulbs, the twin-filament P21/4W ones that is the rear fog too on the RHS?

25 minutes ago, sepulchrave said:

More likely to be the switch unit, they are known to fail, however you can test the circuit by leaving the indicator on and switching the ignition off, one of your side lights should remain lit.

thanks, i'll go and give this a go now

10 minutes ago, Wino said:

Have you definitely changed the correct bulbs, the twin-filament P21/4W ones that is the rear fog too on the RHS?

yeah, the exact same ones that were working not too long ago

41 minutes ago, sepulchrave said:

More likely to be the switch unit, they are known to fail, however you can test the circuit by leaving the indicator on and switching the ignition off, one of your side lights should remain lit.

just tried it, my front lights work, nothing on the back. i tried indicating left and right, only the fronts worked. not sure where to go from here. garage maybe?

Double check that the bulbs are inserted correctly.  I think they can be forced in the wrong way round.

 

Does your car have the bulb failure warning system?

 

Edited 9 December, 20196 yr by Wino

10 minutes ago, Wino said:

Double check that the bulbs are inserted correctly.  I think they can be forced in the wrong way round.

 

Does your car have the bulb failure warning system?

 

checked the lights, they are 100% in the right way. had a friend test the connector, and there was no voltage at all. we had voltage on the brake light and indicator and fog, just not the sidelights...

Will have a look at the circuit diagrams for you later if I get a chance. 

Just now, Wino said:

Will have a look at the circuit diagrams for you later if I get a chance. 

thank u. i appreciate it. i can always take it garage if i need to

1 hour ago, Pudds said:

thank u. i appreciate it. i can always take it garage if i need to

No problem, but it would help to know if the car has bulb failure warning system, as that obviously changes which circuits apply.

4 minutes ago, Wino said:

No problem, but it would help to know if the car has bulb failure warning system, as that obviously changes which circuits apply.

i'm uncertain if it does have the bulb failure warning system. from previous experience, i do know it has a warning light come on the dash when my brake switch broke, when i first had the car (it looked like a coil light on the dash). not sure if this helps?

Probably not then.

Do the number plate lights work?

1 minute ago, TMB said:

Do the number plate lights work?

yes. brake lights, indicators, rear fog, reverse, all of them work, just no sidelights

OK thanks. Just looking at the wiring diagrams.

So the front and rear side/tail lights are fed from 5 amp fuses 33 (right) & 34 (left). Wire colours are - left tail light grey/black and right tail light is grey/red. You should have 12 volts at those wires with side lights on. Brown on each side for earth.

 

Check those wires for 12 volts and check the earth.

Edited 9 December, 20196 yr by TMB

If the bulbs are definitely the correct ones ( 566, 12v 21/4 watt, offset pins) I would suspect an earth problem.

 

Edited 9 December, 20196 yr by TMB

2 hours ago, TMB said:

So the front and rear side/tail lights are fed from 5 amp fuses 33 (right) & 34 (left). Wire colours are - left tail light grey/black and right tail light is grey/red. You should have 12 volts at those wires with side lights on. Brown on each side for earth.

 

Check those wires for 12 volts and check the earth.

thank u. i'll give them another look at tomorrow, and see if any progression is made. i'll post an update as soon as possible. thanks again all

 

Do you have a feed at the tail lights at all? 

48 minutes ago, Damo152003 said:

Do you have a feed at the tail lights at all? 

not sure what u mean by feed. it's just a very basic light setup. not sure how else to describe it sorry

Do you have any voltage reading on a multimeter at the plug for side lights, or probe where the bulb sits if you dont know which pin it is. 

All you have to do is pull the multiplugs out of the bulb holders and test the wire colours I gave you for 12 volts with lights on. The tail lights are fed from the same circuit as the front side lights so if they are working it can't be much else other than a break in the wires or a dodgy earth at the back.

19 hours ago, Damo152003 said:

Do you have any voltage reading on a multimeter at the plug for side lights, or probe where the bulb sits if you dont know which pin it is. 

we tested all pins, and voltage to majority of them, just not the ones we assumed were sidelights

Items 23 & 24 are the tail lights....

 

Lee- if it's a HR earth problem, them a meter will show circa 12v between lamp pins 2 & 3. Far better way is to connect a sidelamp bulb  across pins 2 & 3 and then measure voltage. With a good supply ( +12 nom) and a good earth, the reading will be the same as that of battery ( give/take a small voltage). If there's a bad earth / supply voltage, then the voltage read will be a bit lower. ( Bulb will draw the rated current through any HR).