Q5 Headlight

[Boydie]

We were getting a failed light fault on the Q5 on drivers side. When you start the car, light works but when driving, it will go off and fault comes up on the dash.

I changed the bulb just thinking it was on its way out but same symptoms - works fine but driving, fault light comes on.

Scanned the car and 00979 fault comes up:

Bit lost what to do next as the headlight is buried in around all the engine components

It’s MOT is next Saturday so need to get it sorted today as taking it somewhere will be quite difficult.

Any thoughts?

 

[Coog]

At a guess it could be a broken or frayed wire. Will it sit on the driveway with the headlights on and be OK? Movement is then causing the short as the wire moves.

If it’ll work for the 30 foot required to go from lane to light tester it should be OK for MOT lol

 

[CharlySkunkWeed]

We were getting a failed light fault on the Q5 on drivers side. When you start the car, light works but when driving, it will go off and fault comes up on the dash.

I changed the bulb just thinking it was on its way out but same symptoms - works fine but driving, fault light comes on.

Scanned the car and 00979 fault comes up:

View attachment 424832

View attachment 424833

Bit lost what to do next as the headlight is buried in around all the engine components

It’s MOT is next Saturday so need to get it sorted today as taking it somewhere will be quite difficult.

Any thoughts?

Did you get a good look round the wiring loom and plugs etc ? No corrosion or anything on the pins ? Did the new bulb plug in securely? (No loose pins ?)

 

[Boydie]

Did you get a good look round the wiring loom and plugs etc ? No corrosion or anything on the pins ? Did the new bulb plug in securely? (No loose pins ?)

There is only one plug that goes into the bulb (3 pins) and seemed secure but I’ll just have to strip it again and check. Just seems to go off when driving.

 

[CharlySkunkWeed]

There is only one plug that goes into the bulb (3 pins) and seemed secure but I’ll just have to strip it again and check. Just seems to go off when driving.

Maybe be worth checking wiring diagram in case it comes from somewhere else that's got a issue. PITA that the MOT is so close.
Kinda makes you realise aswell that not all those who you see on the road with a bulb out are numpties.

 

[_James_]

If it working on the driveway, start doing the wiggle test on the wiring.

 

[Gavlar]

Do these have modules or something? Remember a Golf R on here had headlight problems and the module had fallen off or something.

Impressive mileage btw

 

[Alexmck]

Swap headlights round and see if fault moves to other side, it will tell you if problems in the headlight or in the wiring

 

[Boydie]

After some research, fingers are being pointed at the control module but its 50/50 whether or not thats the case - I guess I could swap them over to see if the fault travels as the bulb will now go out after about a minute of idling

Can get one for sub £50 on autodoc but unsure of all the brands if anyone has experience?

https://www.autodoc.co.uk/spares-search?keyword=8K0941597C

OEM one - what would you suggest to replace? Can only imagine the OEM is £100+

Can even get them on amazon

https://www.amazon.co.uk/ADAURIS-Headlight-Ballast-Compatible-8K0941597E/dp/B0CKW3RJFD/ref=sr_1_1?adgrpid=1187473456694046&hvadid=74217310011506&hvbmt=be&hvdev=c&hvlocphy=41471&hvnetw=o&hvqmt=e&hvtargid=kwd-74217226329363:loc-188&hydadcr=20046_2253153&keywords=8k0941597c&qid=1707731215&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

 

[lennyd]

Had this on the wife's a4. Swapped the ballast over and the fault moved so ordered one from a place in England. Audi were looking silly money for it and got a bosch one for about 100.

Quick look finds this

Mitsubishi OEM HID Xenon Headlight Control Unit Ballast 8K0.941.597.C Audi VW

Huge Selection of Mitsubishi Xenon Headlamp Control units, HID Ballasts, HID Bulbs & Ignitors. Make Big Savings Compared to Main Dealers!

www.hids-direct.co.uk

 

[Boydie]

Had this on the wife's a4. Swapped the ballast over and the fault moved so ordered one from a place in England. Audi were looking silly money for it and got a bosch one for about 100.

Quick look finds this

Mitsubishi OEM HID Xenon Headlight Control Unit Ballast 8K0.941.597.C Audi VW

Huge Selection of Mitsubishi Xenon Headlamp Control units, HID Ballasts, HID Bulbs & Ignitors. Make Big Savings Compared to Main Dealers!

www.hids-direct.co.uk

Good to hear - MOT is this saturday so think I will just go with the Amazon one for next day and fingers crossed

 

[Boydie]

Update - ordered a chinese knock off, expectations were high when it arrived....

Was physically smaller than OEM but the holes lined up

And bingo - worked and stayed on

So from changing the bulb, the passenger side was a different shade so thought while I was at it, I will change it too - another strip down and had to move the power steering fluid tank away which was a PITA and lost a bracket into the deep to be lost forever - fortunately had a work around so wasnt worried.

Bulb eventually installed, everything was so tight in the back of the headlight and cables are so short. Tested and happy, so I started to put everything back together.

Final test before getting sorted to bed then....

WTF!! Exact same as the right hand side. Light comes on with ignition then after a short period of time it goes off (leaving the right light on).

So in the case of the right hand side:

• OEM bulb was cutting out after short period of time
• I changed bulb to aftermarket
• Fault still present
• Changed module with aftermarket
• Right hand side working

In the case of the left hand side

• Nothing was wrong except shade of light
• I changed bulb to aftermarket
• OEM module still in place
• Left hand side faulted exactly like right

I have ordered another module just by some coincidence it has faulted for what ever reason and fingers crossed - really thought I had it

 

[CharlySkunkWeed]

There isn't some specific procedure you're meant to do when changing bulbs ? Not that you'd think it would matter but who knows.
Anything in the book about changing bulbs ?

 

[Boydie]

There isn't some specific procedure you're meant to do when changing bulbs ? Not that you'd think it would matter but who knows.
Anything in the book about changing bulbs ?

The video I followed on YouTube didn't suggest anything like that but will look into it but it would suggest there isn't a procedure if changing the bulb and module on the right hand side worked - she's working tonight and module isn't to arrive until tomorrow so will tackle it tomorrow evening and hope for the best

 

[Boydie]

Ok update again - new chinese module arrived yesterday, installed, tested, sat in the car for 5+ minutes and lights stayed on

A short drive this morning and lights stayed on - think thats a win!

Now, lets hope it passes MOT tomorrow morning and doesn't fail on something stupid like headlight alignment - any quick way at home to check this? She is out in it all day and evening to work so no chance of getting it properly done before tomorrow morning (0845)

 

[CharlySkunkWeed]

Ok update again - new chinese module arrived yesterday, installed, tested, sat in the car for 5+ minutes and lights stayed on

A short drive this morning and lights stayed on - think thats a win!

Now, lets hope it passes MOT tomorrow morning and doesn't fail on something stupid like headlight alignment - any quick way at home to check this? She is out in it all day and evening to work so no chance of getting it properly done before tomorrow morning (0845)

Can only think if you see where the s3 lights up your garage door and get the Q5 to match ? Will at least give you a rough idea.

 

[Coog]

Yes take it to a flat level car park and check the lights are roughly level by marking a wall then driving back a short distance and confirming they’re still at the same height and same break over point. There should be a tick up to the left on each light starting in the centre.

I remember getting dogs abuse on here for asking the same thing. 15 years later I still haven’t had to pay for a headlight set lol

 

[Boydie]

Driveway is a slight incline so have to find somewhere quickly or just wing it

 

[Sham1]

The mark the wall, then drive back and check will give you a rough idea. They should actually be slightly lower the further back you go. Normally says on the headlight but it’s around 1 - 1.5%. So mark the wall with tape where the top of the beam is, drive back 1m and it should be 1cm lower. This is all on the dip.
I had a car fail for being too low, so don’t be setting them the same height as the S3, as they will be sloped down too much.

 

[Boydie]

No time really so will just wing it and fire it in - fingers crossed

 

[Boydie]

 

[lennyd]

On?

Hers failed on Thursday. Missed a broken spring on the back, right up in the cup. The coil was still there and in place. 15 mins sorted it yesterday and retest booked for Wednesday

 

[Boydie]

Minor for registration plates which is a first for me in 20+ years

Majors for headlight alignment and uneven wear on rear tyres which I could argue but is what it is

Just got sorted there at Gilnahirk - phoned around a few places and they were able to see me straight away and didn't charge for the headlight alignment

Retest booked for 1630 in Lisburn couldn't book it on my phone so missed out at Ards for 1330, 1420 and 1730

 

[CharlySkunkWeed]

Minor for registration plates which is a first for me in 20+ years

Majors for headlight alignment and uneven wear on rear tyres which I could argue but is what it is

Just got sorted there at Gilnahirk - phoned around a few places and they were able to see me straight away and didn't charge for the headlight alignment

Retest booked for 1630 in Lisburn couldn't book it on my phone so missed out at Ards for 1330, 1420 and 1730

We nearly chanced @Mel plates but stuck them on at the road into the centre.
I've always done it just in case but recently I'd heard that nobody bothers.

 

[Boydie]

Never been an issue since I started driving in 2003 but it’s only a minor so don’t need to do anything I don’t think?