2007 audi a3 no dash lights and wont start

[zu11y]

as title guys. got a 2007 audi a3 thats not starting.
the cluster is completley blank, car starts and then cuts out so is immobilised.

fuses and relays check out fine. i have tried another cluster and its the same so rules out a faulty cluster.

any ideas guys.

[Crasher]

Check the battery is fully charged but is the dash is totally blank at all times? The immobiliser is in the panel and if the panel is dead, the engine ECU will not allow the engine to run. Have you done a full code scan to make sure the ignition switch is working as they are unreliable.

[zu11y]

cheers for the reply. i have charged this battery and it is still the same
cluster is totally dead but so is a second hand unit i tried. i am leaning towards an ignition switch issue.

[Crasher]

You must do a full global scan code read first.

[zu11y]

thanks for the help crasher

to update this thread.

it was the front fusebox that was faulty. using the super technical method of giving it a slap bought the car to life. i tried replacing the ecu relay and it still did the same so next thing was the the fusebox itself.

glad to report this as fixed.

[Crasher]

They suffer water damage underneath and are a bit of a pain to take off. If the terminals in the multiplug get corroded they are a pain in the **** to change and many of the wires so delicate (many are 0.35mm CSA) that you can cause more damage that you started with. The Italians taught us not to put fuse boxes in the engine bay but the Germans thought they knew better.

[zu11y]

haha well said. yhh done a few of these as im a auto electrician by trade. did check the fusebox first but this one was completley dry so did not focus on it too much.

[Crasher]

Did you completely remove it from the car, removing the SA front fuse rail and undoing the centre Torx bolt to raise it up and disconnect it from the large multi pin base plug, turn it over and check for corrosion damage to the pins?

[zu11y]

yh mate. stripped it down, the car side was ok. i cracked opened the fusebox and noticed that the inside of it had water damage consistent with people working on the fusebox in rain.

[Crasher]

I have seen a number of cases now where the lid has let water in when people pressure wash the engine bay, especially after used car sales prep.

[zu11y]

yh same here. i dont get how thik people can get.

water + electricity are not the best of friends yet we see many cars develop issues after being washed.