Electrical Fault

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Nitro182

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Alright all

Just a niggly electrical fault on my 2003 b6 S4 ! Basically my headlights/rear lights ,side lights and indicators/hazzards werent working. (From start up) . Brake lights were fine.

I drive and then arrived home , let the car rest for 20 minutes while researching the fault. I then went back to the car , unlocked it , opened the door , left it for 30 seconds and then the hazards started to flash (normal) , put the keys in the ignition and believe it or not the lights/indicators worked again as they should.

Any idea what this could be?
 
Check for water ingress in the convenience module under front passenger footell in front of the seat & central electrics module tucked under dash drivers side.
 
I had very similar issues last year and as @NHN said, it was water ingress into the convenience module that had damaged the circuit board. I bought a used one from ebay, fitted it and all good again.
 
Thanks for your reply both of you !! I will have a look this evening and update this thread . Cheers !
 
Just checked and the passenger and drivers footwell are bone dry ! And the drainage beneath the battery is clear ! I have played around with it and been for a quick spin , the lights worked when I had got home and restarted the car , however the hazzards/indicator wouldn't work.

Central locking is fine aswell are the heater and stereo.
 
It might still be worth removing your convenience module and opening the cover to check out the circuit board. Your symptoms do still point to that being your problem.

This is what mine looked like when I opened it. You can see the discolouration clearly.

How long have you had the car?

IMG 20190814 182517332
 
I guess you are right , I will remove it on Saturday morning and see what it looks like. I have had the car since Monday , first I test drove it on Saturday (a good 1 hour with it) , had a 2 hour drive home on Monday , no issues whatsoever .

Crazy. Anyone got a vag com in Northamptonshire ?
 
I'd only had mine for a few weeks when it started playing up. Under the carpets were dry as was the plenum chamber but I could see that it had flooded in the past as there was some corrosion in the relay box under the ECU. Previous owner had probably cleared up all signs of water ingress and traded the car in. I bought it with a list of little problems I had to sort out.
 
I am having the same problem I think I would appreciate it if anyone could help. My keys not working. The climate control light stays on after switching car off draining battery. Alarms and hazards going of. No lights on the numbers on the cluster. The cluster control button don't work. Keys not syncing. The signal indication lights don't come up when signaling.
IMG 20200429 WA0012
 
Nitro182 said:
I guess you are right , I will remove it on Saturday morning and see what it looks like. I have had the car since Monday , first I test drove it on Saturday (a good 1 hour with it) , had a 2 hour drive home on Monday , no issues whatsoever .

Crazy. Anyone got a vag com in Northamptonshire ?
Click to expand...

I was completely new to all this when mine started playing up. If you've not done it before then this video is very useful for accessing and removing the module.

 
Monzta said:
I was completely new to all this when mine started playing up. If you've not done it before then this video is very useful for accessing and removing the module.

Click to expand...

Cheers mate ! I watched a video yesterday ! will give it a go tomorrow! Im hoping i only need to dry it out as i recon the recent rain has caused this because the car was absolutely fine before hand !

Im glad you sorted your car out in the end ! If i buy a module will i need Vag Com to code it? even if its second hand?
 
Well I went for a drive this morning ! The lights worked absolutely fine !! And have been working perfectly all day. Will keep my eyes peeled to see exactly what is going on ! :D
 
Nitro182 said:
Well I went for a drive this morning ! The lights worked absolutely fine !! And have been working perfectly all day. Will keep my eyes peeled to see exactly what is going on ! :D
Click to expand...

Flippin' cars, they're a pain in the crack at times. :wtf:

When it next rains will be the test.
 
Monzta said:
Flippin' cars, they're a pain in the crack at times. :wtf:

When it next rains will be the test.
Click to expand...

Defo something to do with the rain ! If only we lived in a nice warm dry climate ! Wouldnt ever have an issue then !
 
Nitro182 said:
Defo something to do with the rain ! If only we lived in a nice warm dry climate ! Wouldnt ever have an issue then !
Click to expand...

When my module got wet, I found that though the plenum wasn't flooding, rain water was trickling under the ECU housing and then dripping onto the module directly beneath. When I lifted the housing I found the foam seal was breaking apart and there were quite big gaps in it. I scraped all the foam off and replaced it with a couple of layers of butyl tape. It's been dry as a bone since.
 
Monzta said:
When my module got wet, I found that though the plenum wasn't flooding, rain water was trickling under the ECU housing and then dripping onto the module directly beneath. When I lifted the housing I found the foam seal was breaking apart and there were quite big gaps in it. I scraped all the foam off and replaced it with a couple of layers of butyl tape. It's been dry as a bone since.
Click to expand...

So this was literally a few drops on the module?

Taken the car out again today and still no issues. I have hired a ramp at a garage tomorrow to have a good look beneath it. Loving driving this thing !!!
 
As I'd not long bought the car I don't know how long the leak had been going on for but I don't think it takes too much water to do damage.

My car I think was a bit of a hot potato changing owners about four times in 18 months due I guess to a long list of niggly faults I got lumbered with. I wonder if the electrical fault in the convenience module was one of them. I bought it in the heatwave in last June and the electrics were fine then one day it threw it down and that's when the issues started, lights working intermittently and the wipers died completely.

If it is your module that's on the fritz then it's a cheap and easy fix. Mine cost me £45 and I'd swapped it in a few minutes. No coding required either.

I bet you are enjoying your S4, it's one hell of a car. And that engine! :thumbs up:
 
Monzta said:
As I'd not long bought the car I don't know how long the leak had been going on for but I don't think it takes too much water to do damage.

My car I think was a bit of a hot potato changing owners about four times in 18 months due I guess to a long list of niggly faults I got lumbered with. I wonder if the electrical fault in the convenience module was one of them. I bought it in the heatwave in last June and the electrics were fine then one day it threw it down and that's when the issues started, lights working intermittently and the wipers died completely.

If it is your module that's on the fritz then it's a cheap and easy fix. Mine cost me £45 and I'd swapped it in a few minutes. No coding required either.

I bet you are enjoying your S4, it's one hell of a car. And that engine! :thumbs up:
Click to expand...

And this is the module beneath the steering column ? So buying one second hand wont require coding ? If so then that's great ! I will buy one and replace it just for the sake of it.

Sounds like you have a nice car on your hands ! I like your comparison to a hot potato ! Mine is the same ! High amount of owners but thankfully it has great service history. How can anyone part with these cars ? They are awesome !

Wouldnt fancy using it as a daily though!
 
Yes, that's the one, just under the column. And it's one of the few things in these cars that really is plug 'n' play, no coding required. Definitely worth buying one in case you need it but you'll need to buy one with the exact same part number as your current one.


Another thing worth doing is putting something over it to stop future water leaks getting inside and screwing with the circuit board. I covered the top of mine with that Fablon clear self-adhesive plastic. My daughter uses if to cover her school books so I nicked a bit. But vinyl wrap or anything like that would work just as well.


I'm not sure mine's a nice car just yet, as fast as I fix one problem another pops up. I finally got rid of the last fault code at the weekend when I replaced the GPS antenna just to find it had been replaced with another one that's never come up before. It's fighting me all the way but I'm not giving in. :)

I bet yours is a bit naughty on the fuel, definitely not a daily. A lovely thing to enjoy at the weekends though. :sunglasses:
 
Monzta said:
Did you get to the bottom of your electrical problem @Nitro182?
Click to expand...

Alright mate ! The issues havnt returned since I had them after the rainy day ! Been out in it twice and had no problem at all ! However I have removed the control module, checked the circuit board and all connections. There seemed to be some condensation on the board so dried it off with a hairdryer and installed it again. Havnt checked since as had the air filter off ready to install the spark plugs which are to arrive tomorrow. Will keep you posted once iv given her a spin !.

I have recorded the module serial no so will wait for one to appear on ebay and will just buy for the sake of it.
 
So now you await the next load of rain to see how things go. Fingers crossed eh.
 
Just an update guys and gals ! After experiencing this very intermittent failure the fault has now been resolved ! After finding a £20 body control unit on Ebay I have just fitted this and the issue has now been sorted !

Happy Days . Cheers for your input ! Was much better than Audizine lol
 
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