Bonnet switch

[summerslife]

Ok, so after the A3 went to Kwik-fit yesterday for new cambelt and rear brakes (see Brake Pads and Disc issues thread) I noticed the 'bonnet open' warning light was on. The mechanic had a quick look and said to come back this morning when the guy who did the cambelt was going to be there. So....this morning, also noticed the car wasn't locked when I went to it and the wipers were not working when the car was stationary. Foreseeing a big bill , I went back this morning where the mechanic looked and prodded etc before declaring the bonnet switch (not the catch) had 'gone' - a common fault with Audi's apparently?!
He cleared the fault code and has set the switch to 'open', so convincing the car the bonnet is closed (which it is). I was told the car will run fine and I should have no problems with it whatsoever. To change the switch would mean sourcing the part from Audi but being a bank holiday, I haven't managed to get hold of anyone for a quote.

Would I be OK just leaving it? Indefinitely? Do I really need the switch to be there?! What sort of costs would I be looking at if I did replace it?

[Mike Foster]

You don't say which model you have ( 3dr, sportback, year, 8P or 8L chassis ) but you can only get the microswitch separately for the sportback.

The number for a 2006 model sportback microswitch is 8P0 953 236 A.

If you have a 3 door you have to buy the flaplock with microswitch and the number is 8P0 823 509 D

Flaplock with microswitch is about £30 and microswitch only is about £20

All this info is from ETKA Rev 7.2 electronic parts catalogue.

Hope this helps

Cheers

p.s maybe the sportback microswitch would fit the 3 dr anyway if you can get the old one off !

[summerslife]

Sorry - its the 5dr sportback 2005 model. Well those prices seem ok for when I do get it done! Maybe not as bad as I thought

[Mick-]

Similar question - 2005 5-door but bonnet open indicator is intermittant, causing the alarm to trigger. Where is the switch located and could it be simply damp getting in causing the switch to appear to have "closed"?

Thanks.

You don't say which model you have ( 3dr, sportback, year, 8P or 8L chassis ) but you can only get the microswitch separately for the sportback.

The number for a 2006 model sportback microswitch is 8P0 953 236 A.

If you have a 3 door you have to buy the flaplock with microswitch and the number is 8P0 823 509 D

Flaplock with microswitch is about £30 and microswitch only is about £20

All this info is from ETKA Rev 7.2 electronic parts catalogue.

Hope this helps

Cheers

p.s maybe the sportback microswitch would fit the 3 dr anyway if you can get the old one off !

[Mike Foster]

Try removing the switch and connecting the wires together. If that removes the fault then that is the problem. Replacing will fix it.

I think the switch is actually in the bonnet lock itself. You may have to remove a few screws etc. but anything with wires going to it will be the switch !

[Mick-]

Thanks Mike - extracted the switch, traced the wiring back to the connector and disconnected the switch: problem removed! Well, the bonnet registers as closed irrespective of whether or not it is so at least the alarm is working again, well, in all respects bar the bonnet.

Just need to buy and fit the new switch - as you say, part no. 8P0 823 509 B

Try removing the switch and connecting the wires together. If that removes the fault then that is the problem. Replacing will fix it.

I think the switch is actually in the bonnet lock itself. You may have to remove a few screws etc. but anything with wires going to it will be the switch !

[pudding]

Hi Mick, Ive got exactly the same problem and the same part number for the switch. Where exactly did you disconnect the switch to solve the false open problem.

I have taken the microswitch off the bonnet latch, but couldnt really see where I can disconnect the switch by following the wiring. Is it difficult to find and does anything else need removing before you can disconnect it?

Also, whereabouts can I buy a replacement?

Cheers.

[Mick-]

OK, first the bad news - I ended up ordering one from my local Audi Centre. That said, they were very efficient but the cost was about £30 because it was the type that comes complete with the bonnet latch. You may be lucky and find yours is the type that Audi sell without the latch - it's about £10 cheaper. To me it was a bit annoying because I did not need nor use the new latch - to speed installation I simply unclipped the new switch and attached it to the old latch, in situ.

As to disconnecting the wiring on the old one - which clearly you'll need to do in any event when installing the new one - the wire from the switch is routed between the top of the radiator and the front grill, past the air intake trunking towards the left side of the car and the multiplug connector is at the left side of the engine-bay, clipped to the inside of the front panel at about headlight level, probably between the left headlight and the left edge of the radiator.

The switch wire (which is about 18-24" long) is held in place with maybe 2 self-grip clips - I found that by carefully but firmly pulling the wire away from me, towards the engine, starting from the bonnect latch end, the clips eventually let go and you can then see where the connector is - even in daylight I needed a decent lead-light to see it (black wires against a black background, in shadow...) and the space the wire passes through is too small to insert even very small fingers.

The new switch lead comes complete with at least one self-grip clip attached.

It's not a difficult job - a bit fiddly but largely because it's not at all obvious where the wire goes! Hope that helps.

Hi Mick, Ive got exactly the same problem and the same part number for the switch. Where exactly did you disconnect the switch to solve the false open problem.

I have taken the microswitch off the bonnet latch, but couldnt really see where I can disconnect the switch by following the wiring. Is it difficult to find and does anything else need removing before you can disconnect it?

Also, whereabouts can I buy a replacement?

Cheers.

[pudding]

Yup that helps a lot, thanks. I now know where to look to disconnect and remove the switch. Fingers crossed my fumbling hands can cope.

The part number on my switch is the same as you posted above, so I also don't need the latch just switch, so hopefully I can source just that for the cheaper price.

Cheers.