Technical Side Repeater Light not working - how to fix ?

[Jack]

My car just failed MoT on a couple of issues, one being that the drivers side repeater light wasn't working, a broken bulb being suspected. However, I have now got the whole of the repeater assembly out and hanging by wires BUT the bulb filament looks OK and, when I tr several bulbs with correct fitting that I happen to have 'in stock', none of these will work either.

I'm kinda guessing that there may be no power reaching this one light assembly, though all the others are flashing just fine, when I click on Hazard Warning.

Any ideas, please, as to why & how to fix ?

 

[steveras57]

if all the others are working then its not a fuse or relay problem! so its either a faulty bulb holder or broken wire or bad connection!

 

[Jack]

I have a multi-meter but (TBH) little understanding on how to use it, unfortunately! (I tried it set on 20 volts, then pushed probes in on the two 'sides' of bulb holder - didn't get any reading but maybe I'm doing it wrong!)

 

[varesecrazy]

I have a multi-meter but (TBH) little understanding on how to use it, unfortunately! (I tried it set on 20 volts, then pushed probes in on the two 'sides' of bulb holder - didn't get any reading but maybe I'm doing it wrong!)

20v range is fine

But you should see "something"

If in doubt.. Place across Battery terminals

Should see 12 volts ( + or - 1 volt)

Normally I would see 5 or so volts at those bulb connectors, and trace back down finding a cable plug corroded

Cleaning the connectors gets the voltage up to a sensible figure

 

[Jack]

Thanks - I will check it across the battery (tomorrow, now) but fully expect that it will indeed show c.12V, tbh - it seems odd that there seems to be no power at my bulb holder though - is it possible for me to go a little bit 'back down' the actual cables and somehow read if there is power/earth in them? (through the insulation or- more likely, I suppose - by poking the metal probe in to touch the 'copper' wire - ? )

 

[yann]

Hi, as you have a few unknowns'....pop down to your nearest 'discount store'...get a cheap volt probe...(led type) clip to earth, probe your repeater terminal
if no feed, put clip on batt pos, check if earth shows on terminal....
if 'no one's at home' it's a case of 'follow the river'...Hth , Yann

 

[Jack]

Yann : thanks, good idea, I think I've actually got the thing that you mention, have used on house mains but never thought of it for car ! (guess & hope it will pick up car voltages, as it picks up 'house' power)

 

[varesecrazy]

Thanks - I will check it across the battery (tomorrow, now) but fully expect that it will indeed show c.12V, tbh - it seems odd that there seems to be no power at my bulb holder though - is it possible for me to go a little bit 'back down' the actual cables and somehow read if there is power/earth in them? (through the insulation or- more likely, I suppose - by poking the metal probe in to touch the 'copper' wire - ? )

There may well be a join.. Plug and Socket..

Look further down the cable

 

[John202020]

Your house tester won't work for the car.
Here's a picture of my meter, note the voltage range is set to dc (car) solid line with the dotted one above, also must be in V and common, NOT A(amps) and place the black prong on a good clean earth point when testing for a live supply?

 

[The Panda Nut]

Yann : thanks, good idea, I think I've actually got the thing that you mention, have used on house mains but never thought of it for car ! (guess & hope it will pick up car voltages, as it picks up 'house' power)

Mains one willnot work on 12v unless you are very lucky. I have a tester with aligator clip on the end of a wire the other end is a sharp probe with a screw on cover. When it gets a 12v circuit it lights up. A cheap thing from The Range shop. Worth its weight in gold.

 

[Jack]

UPDATE : Fitted brand new bulb (but still not lighting up) / tested multi-meter across battery (shows 12.55V) / ran test light from battery + to the lamp holder (earth is OK, test light comes on) / ran wire from battery -, through test light, touched proobe to lamp holder + feed (no light shows).

So it seems that my problem is "no power to bulb holder" - guess I need to find where that power feed cable comes from, does anyone happen to know where I can locate it, please?

 

[John202020]

Use your meter on the bulb holder, stick the black one on a good clean known earth, now check for a feed, I say this as your test may show a false outcome, ie the bulb lights connected the live feed( earthed via the other indicators on that side ), when actually it's lost the neutral, possibly?

 

[Jack]

Righto - connected the multi-meter black probe direct to the battery, then used red probe to touch terminals inside the bulb holder - there was no reading when I touched (what I thought to be) the positive/feed wire side, shown on photo as the lower, mostly blue wire BUT I saw a 'beat', flasher-regular reading on the mainly black, upper in photo wire, which I thought was the earth wire ! It was only 0.01 as a reading but I'm somewhat mystified now !

 

[A3jeroen]

IIRC it is possible to push a 5W5 bulb in the holder 90 degrees out. (been there done that)

gr J

 

[steveras57]

From what i can see the blue/black wire is the power feed to the bulb holder!.
I think you need to check the wire all the way back to the body control module !.
There are no connectors or joints in this wire its direct from the bulb holder to the bcm!.
I would guess that the wire runs in the loom inside the inner wing through the bulkhead then along behind the instruments/ facia to the BCM in the passenger footwell!.

As you have to take the glovebox cubby , and part of the facia off to access the BCM ( which itself is hidden behind a metal security plate) and much of the loom might prove inaccessible this could be a tricky and frustrating task so in this case might be worth handing it over to an auto -electrician however as one last thought before going down that road as i said the bulb holder itself MIGHT be faulty!.
To test that you could cut a TINY bit of the insulation from both the black and the black and blue wires and repeat your power tests direct onto the wires on the off chance you find proper 12v power there then that proves the bulb holder to be faulty!.

If however still no power then it can only be either a faulty(broken or shorting) power supply wire! or the black earth wire has no continuity( is broken) so the circuit cannot be completed!, if both the wires show continuity from end to end then the final alternative is that the BCM module has an internal problem and is not suppling voltage to the circuit! which then makes things frighteningly complex and potentially very expensive!.
Heres hoping its a simple(r) break in a wire or short circuit! .
I wish you luck mate!.

 

[Jack]

Thanks Steveras57 - quite alarming prospects but, for now, I will try the nick in insulation test..........

 

[Mike1alike]

I don't think you need to nick the insulation. I think that if you unclip the plastic clips you can take out the wires together with their contacts. And there you'll have direct acces to the wires and the possibility to clean the contacts. I think you have the 12 V there and the problem is the contacts being oxidized.

 

[Jack]

Mike1alike : Thanks for idea of unclipping wires and getting at their contacts - will probs try this, tomorrow now as light fades....

I did actually try the 'nick cable insulation' idea - I may have been too light in my cutting (though I thought I could see actual carrier wire but maybe not enough to make good contact with??) - anyway, I couldn't get any reading on either wire that way, so I then pushed probe, carrying '+' power direct from battery via meter, into the earth terminal and saw 12.3V, so it looks like the earth terminal is working OK, with '+' power still the most likely culprit, tho' now subject to the idea of wire unclip & clean up.

In all of this, I'm struggling to think of a reason why the light has'suddenly' stopped working - could perhaps be oxidised terminal has built up to point of preventing power reaching bulb - certainly hope so !

 

[John202020]

Can you take another more clear picture of the rear of the plug, is it me or is there signs of corrosion on the blue wire where it meets the plug?

 

[Jack]

Hum - it's dark now, of course, but I will indeed check this out tomorrow - now that you mention it, there is 'something' evident there, which I had dismissed as just a shard of wire but could be summat else!