Boot close sensor

David

Member
I'm sure this issue must be here somewhere, but I can't find it!
My 2005 TDI does not recognise when the boot is open, so if I unlock the car and open the tailgate, it will lock again if I haven't also opened one of the doors. Additionally the boot light does not work as no power is getting to the bulb. I've replaced the boot catch / microswitch with a used version, but this hasn't changed anything. Do I have to buy a new catch (if available) or is the problem elsewhere?
 
I'm sure this issue must be here somewhere, but I can't find it!
My 2005 TDI does not recognise when the boot is open, so if I unlock the car and open the tailgate, it will lock again if I haven't also opened one of the doors. Additionally the boot light does not work as no power is getting to the bulb. I've replaced the boot catch / microswitch with a used version, but this hasn't changed anything. Do I have to buy a new catch (if available) or is the problem elsewhere?

Hi David, I have a similar problem on my 2004 TDI90 but in opposite. My boot always thinks it is open despite being closed! The boot light will remain on, I get the dashboard warning light of boot open all the time, and I get no flashing light on the drivers door to say the alarm is active. It's driving me mad! Have fitted a new boot catch (used one) and all worked well for about an hour or so when that failed and the problems returned. Loathed to spend £60 from AUDI on a new catch; especially if this does not resolve the issue. How did you go about changing the micro switch in your vehicle? Do you have to remove the lock from its plastic outer (seems one unit to me)? Any idea what the code for the microswitch or where to find a suitable replacement on ebay if you have sight of the beastie?
 
Could it be a failing cccu? Being 2004 and 2005 models it would be an AF cccu which have proven to be very reliable but perhaps things are changing now they are over 10 years old.
 
Hi David, I have a similar problem on my 2004 TDI90 but in opposite. My boot always thinks it is open despite being closed! The boot light will remain on, I get the dashboard warning light of boot open all the time, and I get no flashing light on the drivers door to say the alarm is active. It's driving me mad! Have fitted a new boot catch (used one) and all worked well for about an hour or so when that failed and the problems returned. Loathed to spend £60 from AUDI on a new catch; especially if this does not resolve the issue. How did you go about changing the micro switch in your vehicle? Do you have to remove the lock from its plastic outer (seems one unit to me)? Any idea what the code for the microswitch or where to find a suitable replacement on ebay if you have sight of the beastie?

unlikely to be the micro switch itself, they get a lot od stick for be poor micro switches, but it as never been a failed micro switch in my experience. The far more likely cause is failed solder joints where the connector legs meet the circuit board.
They are easily fixed with a good hot soldering iron and ideally some flux and leaded solder. As a bonus on the tail gate the lock assy is easily removed (as against the door locks which are hours of a job to remove and refit)
The micro switch can be easily checked with a multi meter whilst the lock assy is apart, but it normally needs nothing more than a clean with some switch cleaner. If you are really unlucky the plunger on the micro switch can wear down, but this is NOT commonplace
If you still have the old lock assy send it to me and I will sort it for you

Cheers,
 
Hi Paul, Sorry for delay in replying, internet issues! I'd be very keen for you to have a look at it, and can post the original one to you no problem. Where are you? I'm in Bedfordshire SG19. Thanks for your help, David
 
Hi Paul, Sorry for delay in replying, internet issues! I'd be very keen for you to have a look at it, and can post the original one to you no problem. Where are you? I'm in Bedfordshire SG19. Thanks for your help, David

Post it to.
P Whittle
65 leach lane
St Anne’s on the sea
Lancs
FY8 3AN

Put a note inside with your used name and address please
Cheers. Paul


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Could it be that the catch is the problem, not the lock? You can check the lock easily by opening the hatch and moving the lock to the locked position with your finger. It will then appear as locked on DIS; if so the catch in the frame needs adjusting but you have to remove the trim.

RAB
 
Hi All, Thanks for the comments. Can the problem actually be the catch? I've swapped this for another and the issue persists, and from the forum it doesn't seem as though this is a typical issue, so it would seem unlikely that the same problem is present in both catches. I've been out in the snow to check the driver display and it doesn't seem to be communicating to the boot as it would happily let me drive off with it open! The other thread could be the same issue. Any thoughts on where to go from here? Car has otherwise been very reliable and great to own. Thanks, David
 
Hi All, Thanks for the comments. Can the problem actually be the catch? I've swapped this for another and the issue persists, and from the forum it doesn't seem as though this is a typical issue, so it would seem unlikely that the same problem is present in both catches. I've been out in the snow to check the driver display and it doesn't seem to be communicating to the boot as it would happily let me drive off with it open! The other thread could be the same issue. Any thoughts on where to go from here? Car has otherwise been very reliable and great to own. Thanks, David

The catch can and does fail I have had two which have failed. Reflowed the joint and as good as new again
Can re al if the door was showing always open or always closed
Cheers. Paul


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?....... and it doesn't seem to be communicating to the boot as it would happily let me drive off with it open! .........David

I am fairly sure I have driven, by accident/with ladders sticking out and boot open symbol on dash. I don't think it was ever designed to stop you, just warn, but others can confirm.

Andy
 
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I am fairly sure I have driven, by accident/with ladders sticking out and boot open symbol on dash. I don't think it was ever designed to stop you, but others can confirm.

Andy

Agreed it is just a warning not linked to anything other than the interior lights alarm and dash display


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Hi, I realise it is just a warning and wouldn't stop me driving the car, it's just that it doesn't appear to be registering whether it is open or closed. If I take the connector off the catch and join the two wires together would this send the message that the boot is closed, or is it not that simple? Thanks, David
 
Hi, I realise it is just a warning and wouldn't stop me driving the car, it's just that it doesn't appear to be registering whether it is open or closed. If I take the connector off the catch and join the two wires together would this send the message that the boot is closed, or is it not that simple? Thanks, David

Unsure if it that simple if it is just two wires then maybe but thinking about it there must be more wires as the lock needs power and a signal from the switch to undo and another from the central locking to lock


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Hi, the solenoid that opens the boot is separate and operates the catch by a rod. The boot opening switch on the outside of the car operates the solenoid, as does the central locking. The micro-switch in the catch can only be on or off. There are only two wires going to the micro-switch on the catch. I think you may be wasting your time doing anything to the catch / micro-switch, although your offer is much appreciated. Is there a wiring diagram so we can see if the two wires connected together would send the message that the boot is closed? Is the problem more likely to be a broken wire somewhere or a PCB issue? Thanks, David
 
in that case with the connector pulled off you should get either tail gate open or closed and the opposite if the wires are shorted together

If it does not do that then suggest a broken wire, likely to be in the loom as it bends when the tail gate is opened

Cheers,
 
Yes, I agree, now just a matter of how to find / fix it. Has anyone had an issue like this and how did they go about fixing it? Thanks a lot for your help, David
 
My A2 has just developed boot closing issues similar to above but slightly different in that it opens fine and the DIS works showing it is open, however it isn't closing shut. Appears to bounce when you close it as though the catch in the lock mechanism isn't engaging...

Any ideas A2OC folks?!
 
My A2 has just developed boot closing issues similar to above but slightly different in that it opens fine and the DIS works showing it is open, however it isn't closing shut. Appears to bounce when you close it as though the catch in the lock mechanism isn't engaging...

Any ideas A2OC folks?!

I had a similar problem a few weeks ago - it was a bit of plastic (possibly a bit off a cover of some sort) from inside the latch stopping it from "rolling over" and fastening round the hoop on the body. The piece of plastic was inside the lock, the hook would roll round but not latch.
 
I had a similar problem a few weeks ago - it was a bit of plastic (possibly a bit off a cover of some sort) from inside the latch stopping it from "rolling over" and fastening round the hoop on the body.

Ah cheers for that, sounds plausible. I'll take another look and see if anything is obstructing the latch
 
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