N/S Headlight staying on

[Darran]

Seem to have a problem with the nearside headlight not turning off dip beam. Stays on even with ignition off ? Is my car special LOL. Gonna put the vagcom on it tomorrow and put my cyber hand up its skirt!
Anyone else had this problem ?

 

[vr6gordy]

Could be the head light switch at fault

 

[vr6gordy]

Disconnect the light switch and see if it goes out

 

[Darran]

Will do in the morning, do these have lighting ecu,s or are they still relayed ? 03 plate 1.8t cabby.

 

[Mike.M]

Have you checked that the indicator stalk is in the central position when parked up?

Otherwise as mentioned could be the main switch in the car

 

[Darran]

Thanks for replies , right now the battery is charged im off out to put vcds on the car and see what it comes up with.

 

[hades-]

could be the CEM there common for getting wet.

 

[Darran]

whereabouts do i locate the CEM ?

 

[john777w]

Under the carpet passenger footwell

 

[Darran]

I moved the P/S seat back

 

[VagCabby]

Ouch, surprised anything electric was working!

 

[dualmono21]

get it in the airing cupboard for a couple of days to dry out
you might be lucky , then have a look on ebay for a new ccm with the same part number

 

[Darran]

It was just lying under the p/s seat not connected, it must be an old unit as central locking and remote works fine.

 

[hades-]

that's not for the lights that's the ccm

the CEM is drivers side remove lower panel under steering wheel and its up on the right

that you have under the seat if for the locks etc.

 

[Darran]

Thanks very much Hades, yeah ive checked and there is a new unit fitted, i suspect the alarm horn shorted and blew that unit because alarm horn is disconnected and VCDS says that alarm horn is shorting.Thanks again , tomorrow i will be mostly contorting myself to get to the CEM.

 

[hades-]

just check it for any water easy to open.

but it normaly comes up with a fault code

 

[Darran]

00978 - Lamp for Low Beam; Left (M29)
57-00 - Electric Circuit Failure
01519 - Bulb for Back-Up Lights; Right (M17)
57-00 - Electric Circuit Failure
01502 - Bulb for Rear Fog; Left (L46)
57-00 - Electric Circuit Failure
01800 - Light Switch (E1)
27-10 - Implausible Signal - Intermitten

I know the fog light and reversing light bulbs are gone which just leaves the other 2 faults

 

[hades-]

id say water in the cem then but you need to find out where its getting in.

could be from pass side as looks like old owner had the blocked drains and could have worked over.
or seal on the ecu box cover is letting water in I would check this aswell as it can **** the relays etc up that live in there.

 

[Darran]

will do thanks very much, will post results tomorrow too cold to go out now and mess with it.

 

[vr6gordy]

Just gonna say check the ecu box the. Reseal it with silicone

 

[hades-]

I know the silicone is a good idea but the seal or a new lid aint many £££ from audi.

and with the flexing temps etc silicone can and will fail OK for short term but not a long term fix.

 

[Darran]

So here,s the lighting module , cant see a lot wrong myself?

 

[hades-]

looks dry
I would still get it scanned
where are you from ?

 

[Darran]

scan results are further up this thread, i will rescan the module on its own.
Oh and near Derby.

 

[Darran]

Hmmmm i have this little ******** in the top of the dash which seems to be a light sensor?

Now this being said solar light sensor, would this mean that my main light switch should have an AUTO setting on it ?

 

[frankc]

I remember reading somewhere that sensor is connected to the climate control and is used to detect direct sunshine shining through the windscreen.

Both my B5 and my B6 had that sensor, only the B6 has auto headlights - the headlight sensor is in the back of the rear view mirror.

Frank

 

[hades-]

its nothing to do with auto lights

 

[vr6gordy]

Any of your mates got the same car as you ?? Try there headlight switch in your car

 

[demus]

Not sure on the output design of the electrical control module, but I would suspect the outputs are switched using semiconductors.
If these fail they generally fail to a short circuit, leaving the output permanently on....

Should be module 09 - central electrics on VCDS.

 

[Darran]

Well ive interrogated the ecm till it was sore but it shows no faults and thinks the light is off when clearly it isnt, as the feed wire from the ecm to the N/S/F headlight dip is live with 12+v so im gonna buy another b6 convertible and swap the ecm over , im convinced the ecm is faulty. On the bright side ive got the roof working

 

[demus]

Try pulling the fuse that feeds the central electrics module, its a small 7.5 amp fuse if I remember correctly. ( not central convenience electronics ).
Thats the supply for the modules logic control etc, not the outputs, if the headlight is still on then it must be an output faulty.
Has it got standard bulbs or 100 watt jobs in there, the extra current for those may do it in over time...

 

[Darran]

Thanks for replying , i cant find this 7.5a fuse nothing in the fuse box relates to the CEM , is the fuse somewhere else.?

 

[Darran]

Something very strange going on here , this is the wire colour coding and which side it feeds....

The "dipped" connections out of the OPSC unit to the headlights are:
Dipped Beam (L)
J519:T23/23 (yellow/black wire) -to- T17a/16 -to- L Headlight connector 5/56b -to- Bulb M29

Dipped Beam (R)
J519:T23/22 (yellow/white wire) -to- T17ac/16 -to- R Headlight connector 5/56b -to- Bulb M31

Now then, the wire colours on each headlight are as they should be but when i unplug the H/L connector from the CEM and test continuity the yellow/black wire somewhere turns into yellow/white and feeds the right side light instead of left and vice versa.

 

[demus]

Sure there was a fuse in there for it, I'll double check tomorrow..
Your wiring does tie up with my Haynes book of lies, should be pin 5 on the headlight connector, looks like they have got individual outputs from the module..

 

[Darran]

Yes they have individual outputs but im ******** if i know how or why the colours swap over ???? very strange and not factory according to the wiring diagrams ive seen.

 

[Darran]

UPDATE
Today ive been mostly checking volts
It would seem the problem is the CEM as everything is correct apart from i have an open circuit from the CEM to the n/s h/l, testing the pin concludes that voltage is constant no matter wether lights on or off or ignition on or off, new(secondhand) module needed me thinks.
Bin fun though!!

Moral of this story is...........................don't always rely on VCDS or any other diagnostic program as sometimes the modules tell it lies and then it lies to you.!

 

[demus]

Found the fuse, 37, intelligent power module, 20amp. Sure I didn't dream it.

Unless there is a feedback from the output, the module will think everything is fine and so will VCDS.

Try a new module, theres plenty of the gits on fleabay..... hope you get it sorted..

 

[Darran]

I would like to thank you all for your help.

 

[Darran]

I pulled the fuse which was 25 amp but it made no difference light still on , so CEM is on shopping list.

 

[demus]

Hope you soon get it sorted..

By the way, that rod looks the nuts!!