Hazard warning lights not working on my Audi 100!

[Lankytim]

Failed the MOT today on the above, the tell tale on the dash lights up but does not flash when the hazard warning lights are switched on, outside none of the indicators do anything-. The indicators themselves work fine, I assumed that they used the same relay but when I swapped it the problem was still there.

 

Do the hazards have their own relay? I have looked everywhere but cannot find it! The cover from under the steering column is missing so I cannot tell which relay is which.

 

I could kick myself, the hazards have not worked for months- I assumed it would be an easy fix but now i'm going to miss the free retest!

 

If someone can tell me within the next hour I can get it re-tested today!

[trigger]

I would have thought it was a relay but no idea which one it is, Does it not say in the handbook?.

 

I always thought a free re-test was valid for a week.

[Lankytim]

Is it? Might be ok then!

 

Handbook is useless

 

Haynes is fucking useless as usual

[trigger]

It's only valid if you leave the car for them to fix.

 

Your re-test will only be free if the vehicle is left with the original MOT testing station for repair and then a partial re-test is carried out within 10 working days of the original MOT test

 

http://mottesting.org.uk/mot-retest-inf ... -fail.html

[Cavcraft]

http://automotive.become.com/19861986-a ... 1047189547

 

http://www.thefind.com/cars/info-audi-flasher-relay

 

http://www.tyresmoke.net/forum/audi-a6- ... ators.html

[In The Pit]

It wouldnt be the switch thats broken would it? I replaced a heated rear window switch on my fathers Audi 80 recently as it wasnt engaging correctly when pressed in, a new switch from Audi (about £11) and the heated window works.

[Lankytim]

Cheers for the links! Heres a bit of an update.

 

After getting no joy by replacing the indicator relay I decided to replace the switch itself, to do this the steering wheel has to come off and the whole stalk aseembly has to come off. I had a spare from an A100 I broke a few years ago so lobbed that on. Still no luck! However, I had left the ignition on and as I tried to remove the replacement stalks the horn ring shorted out against the steering column, this blew a fuse in the fuse box under the bonnet. I replaced the fuse and hey presto- the hazard lights were restored! Unfortunately now the indicators don't work . I have atleast dicovered that the hazards and the indicators use the same relay (which is behind the instrument binnacle and is a bitch to get out)and that it works. Now I just need to figure out why the indicators have packed up! All the fuses seem ok.

 

On top of this the horn stopped working, this was also a fail point on the test but seeing as it worked before and after the test I didn't understand why the tester had picked up on it. Turns out it was totally knackered with rust and corrosion and had finally popped its clogs while I was working on the indicators. A rover horn I had lying about has cured the problem, but it does sound odd. It kinda sounds like Herbie the love bug on his death bed. Should satisfy the tester though.

[Lankytim]

 

From this diagram I deduce its either the relay or the planet Neptune is misaligned with Pluto, somehow causing electrical interference.

 

The relay is a special one with an additional prong to feed the aftermarket tell-tale on the dashboard for the trailer indicators.

 

 

I'd much rather track down and solve this problem with intelligence and skill, but seeing I'm a bit short on either i'll just start replacing the electrical system wholesale and hope for the best.

[bangers & mash]

Replaced the horn on one of my old Rovers many years ago that sounded shit. I was looking it the old one and I noticed a small adjustment screw, a quick turn and it was back to it's usual tone again.

[scaryoldcortina]

Tim - from looking at the diagram I don't see how it can be the relay (if either hazards or indicators work, it must be ok) but it looks to me like it has power fed to it from two places, depending on if the hazard switch is pressed or not.

 

Looking at the E2-E3 block in your diagram (combined indicator/hazard unit) the RH end has 49 (power into relay) and 30a (hazard power - feeds from S2) and "mystery wire" 138 (this will refer to another 138 on the ignition power control diagram) which will be a switched power feed to operate the indicator switch. Assuming the switch is OK (worked on the other car?) I'd be chasing this wire to find out why the indicators have stopped.

 

PS, if at MoT the horn is weak or intermittant it is a fail.

[Lankytim]

Hey Scary, you were bang on the money- The hazards are fed by a different fuse to the indicators. I had checked the fuses beforehand but after checking them again I found one had blown. I replaced it and.... we now have functioning indicators!

 

There must have already been a blown fuse, one which operated the hazards. When I blew another fuse I replaced the hazard fuse thinking it was the one i'd just blown which was infact the indicator fuse.

 

Can you see why i'm not an auto electrician?

 

Soo, were all ready for the re-test. Horn may be a little too quiet for the tester- I will have to check to see if there is a screw to adjust it. it worked fine when it was on the wifes Rover 214 a few years ago, its been in the garage since.

 

Thats not the end of the story though as theres a new problem- the petrol and temp gauge are now non-functioning. I'm not sure but the dash lights dont appear to work either. All fuses check out. What the hell have I done now??

[bangers & mash]

It's a simple job to do, I have an old one kicking about so I've taken a couple of pics.

 

On this horn, the tone adjustment screw is under the white blob of sealant.

 

 

Remove the sealant and adjust the screw until you're happy with the tone.

 

 

A fresh blob of sealant = job done.

[Lankytim]

I had no idea you could adjust the tone of a horn like this, thanks very much for the info!- this particular horn had a funny problem, when it was unbolted it worked fine, bolted back on it gave out a feeble tinny shitty squeak. Adjusting the screw altered the tone of the squeak, but not the volume. In the end the MOT retest was looming so I went out and bought a new horn for £7 and lobbed it on, job done! The retest went well and the Audi is now sporting nearly 13 months MOT! yay!

[dollywobbler]

Was going to say hit the horn with a hammer. I know my favoured mechanic in Birmingham used a hammer for almost every job, but it did make the horn on my 2CV louder!

[Lankytim]

"Hit it with a hammer" bloody Brummies!

[bangers & mash]

Dave was a grumpy old git that told me how to do it. For what they cost for a new one it's probably just easier to buy a new one, but it's worth knowing if funds are a bit tight.

 

Funny enough though, Dave's favorite tool was a big hammer!

[Lankytim]

The screw tip may come in handy of anyone wants to tune a pair of horns to maximise their lovely noise.

[scaryoldcortina]

http://www.urbandictionary.com/define.p ... crewdriver