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TT Lock Switch -opinions on creating a fix. Got 1 option

65K views 130 replies 34 participants last post by  davebowk 
#1 ·
2018 edit

For the future you can buy good microswitches on eBay now designed for this repair

https://rover.ebay.com/rover/0/0/0?mpre ... 2522346126


HELP NEEDED!

Another not so clever design but maybe we can come up with a solution.

basically a nylon cover wears and the exposed switch head cuts into the latch coating stopping the latch working fully and eventually not having enough to push the switch.

The Switch is mounted with a spring clamp and located with two plastic pins from the body from the body of the switch

NOTE: in the above, there is a metal tab holding the spring clip, this is revised, all earlier locks dont have that, the clip T edge rests against the plastic switch pins to keep it in place.

1. A weatherproof roller switch is going to be a much better option.
2. a little sanding of the damage should recover the latch to allow a roller to work
(or am I flogging a dead horse?, maybe a little epoxy and sanding?)
3. the side shown above must remain fairly flush as that side is close to the bodywork.
4. the switch is a normally open circuit switch, press to make contact.
5. I need some ideas on the switch type and mounting options.

more reference pics.....





 
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#2 ·
Here you go Wak:


Farnell part:
http://uk.farnell.com/jsp/endecaSearch/ ... =gensearch

Clearer datasheet:
http://www.farnell.com/datasheets/26701.pdf

The roller type will take up too much room - they all fall into standard sizes. The roller itself is a 5mm diameter wheel requiring at least 7mm or so room when compressed compared to not a lot with the simple plunger type. So you'd have to back off the body mounting accordingly. Added to that the problem that the roller sticks out, so doesn't operate in the same position on the cam.

The microswitch I'm suggesting is a lever type. What you could do is bend the lever at the end around the switch so it simply forms a protector for the plunger beneath and doesn't catch on anything. The lever would slide on the rough cam surface like a ski/sledge. The operating position will be near identical and the mounting position would be the same.

I think what you could do is smooth out the torn up nylon a bit then mount the switch using two M3 screws washers and lock nuts (or back to back nuts to lock).

The switch is a changeover so normally open or normally closed depends on how you connect the wires.

It's fully sealed to IP67 (immersion in water) and costs a reasonable £3.81 +VAT. Hope that helps :)

P.S. I still think the surface looks as though it's been ripped up by something else, like the end of a too long mounting screw or something - it just doesn't look gradually worn away - more torn with force.
 
#3 ·
Cheers John,

I shall get hold of one and see how it could be used.

Shame a roller cant be found I wonder if the SKI effect will also cut into the plastic only thing is the metal lever could be bent to compensate!

:)
 
#5 ·
Does this help clarify? The cam still presses the actuator button in exactly the same place but the lever is bent out of the way and merely protects the sealed actuator from friction damage and presents a smooth surface to the cam. The thicness of the lever is negligable, the switch mountings are the same dimensions and fitted the same way round as before, with the actuator button in the same position - so the actuator linear movement is the same.


If the switch is mounted the other way round and the cam presses the free end of the lever the linear movement of the actuator, due to leverage, will be too little. The same problem occurs with the roller type - the roller would need to be directly above the actuator, for the same movement, but it's at the other end, losing ~3x the linear movement. You also need the extra space of the roller. Although it would be possible to adjust the switch mounting position - the reduction in the linear movement would make it tricky to adjust and set up reliably.
 
#6 ·
Thanks for the info Wak. Excellent photos too.

Have you made any progress with this? Any luck sourcing a suitable replacement switch? I might be able to get hold of some military spec micro switches which are weatherproof but also have metal plungers rather than the flimsy plastic type.

I'll take a look through my catalogues later to see if any are the correct dimensions. Just out of interest how critical are the dimensions. Is the switch a tight fit or could it accommodate something slightly larger?

Andy.
 
#7 ·
Andy, I am a little involved in this too as we had an issue with mine failing, we swapped it over at the weekend with a second hand one which is ok for the moment.

Symptoms are...

Window dont drop the 5 mm on opening
Interior light dont come on when door opened
Lights on warning buzzer dont work
Car will lock itself with keys in ignition if you close the door and dont start up (it actually locked me out with the keys inside)
Instrument lights dont light up when door opened

Personally I think a metal retracting pin will wear into the cam even more than a nylon one but then what do I know.

Thanks for the suggestion though Andy , you may be right !
 
#8 ·
Hmm, you could be right there John. Also available are metal plunger types with metal levers similar to the one pictured earlier. These might be even better but maybe overkill.

Those are certainly the symptoms I have too. Although I hadn't considered the problem with being locked out. That might be the encouragement I need to do something about it. Until now I'd just seen it as a mild annoyance that the windows don't do their cool little dropping thing when you open the door.

Andy.
 
#9 ·
I have the recommended switches and it looks like it would work well but they are deeper, I have a working prototype but the switch sits in the clip loosly.

I am trying to to decide on a mounting option that is better and will be more solid that isnt going to involve epoxy resin! :roll: :)

I think the metal clip wont be too bad and the beauty is if it does wear a little plastic it can be bent further to take up the slack.
 
#11 ·
TTotal said:
Andy, I am a little involved in this too as we had an issue with mine failing, we swapped it over at the weekend with a second hand one which is ok for the moment.

Symptoms are...

Window dont drop the 5 mm on opening
Interior light dont come on when door opened
Lights on warning buzzer dont work
Car will lock itself with keys in ignition if you close the door and dont start up (it actually locked me out with the keys inside)
Instrument lights dont light up when door opened
I have exactly those symptoms, and have been looking for a fix. I've been quoted over £200 to get it fixed at a local garage (specialising in Audi/VW), and i'm guessing its gonna cost a good deal more from Audi themselves? Anybody had a quote from Audi?
 
#12 ·
Andyman said:
Do the holes in the switch line up with the existing holes in the catch casing? Would it be possible to bolt them through and do away with the metal clip? How about drilling a new set of holes if they don't line up perfectly?

Andy.
no, the switch is deeper so the catch metal covers the holes!
 
#13 ·
Bobstar said:
TTotal said:
Andy, I am a little involved in this too as we had an issue with mine failing, we swapped it over at the weekend with a second hand one which is ok for the moment.

Symptoms are...

Window dont drop the 5 mm on opening
Interior light dont come on when door opened
Lights on warning buzzer dont work
Car will lock itself with keys in ignition if you close the door and dont start up (it actually locked me out with the keys inside)
Instrument lights dont light up when door opened
I have exactly those symptoms, and have been looking for a fix. I've been quoted over £200 to get it fixed at a local garage (specialising in Audi/VW), and i'm guessing its gonna cost a good deal more from Audi themselves? Anybody had a quote from Audi?
the lock is around £82 and about an hour to change over.
 
#14 ·
Wak said:
Andyman said:
Do the holes in the switch line up with the existing holes in the catch casing? Would it be possible to bolt them through and do away with the metal clip? How about drilling a new set of holes if they don't line up perfectly?

Andy.
no, the switch is deeper so the catch metal covers the holes!
Doesn't that mean you could just re-drill the holes and bolt it on with some M3 machines screws?

I found a possible alternative which might fit better but is slight more expensive.

http://rswww.com/cgi-bin/bv/rswww/subRa ... cheID=ukie

Andy.
 
#15 ·
Wak said:
Bobstar said:
TTotal said:
Andy, I am a little involved in this too as we had an issue with mine failing, we swapped it over at the weekend with a second hand one which is ok for the moment.

Symptoms are...

Window dont drop the 5 mm on opening
Interior light dont come on when door opened
Lights on warning buzzer dont work
Car will lock itself with keys in ignition if you close the door and dont start up (it actually locked me out with the keys inside)
Instrument lights dont light up when door opened
I have exactly those symptoms, and have been looking for a fix. I've been quoted over £200 to get it fixed at a local garage (specialising in Audi/VW), and i'm guessing its gonna cost a good deal more from Audi themselves? Anybody had a quote from Audi?
the lock is around £82 and about an hour to change over.
How easy is it to do? idiots guide? and where to get the lock from?
 
#18 ·
Right, I think I can see what's going on now and this might explain. I've used Wak's original dimensions and switch picture and ratio'd on some missing dimensions in light blue, then transposed some other dimensions to the new switch. I've taken corner "X" as a reference and measured the plunger position to nearly match (7.2~7.0, 2.4~2.1). I've placed a scaled square for the old switch body and two blue circles for the old hole positions as best I can.

You can see the problem with the holes. This is unusual as standard micro-switches have identical mounting variants... usually :? Sorry I didn't do this excercise before Wak - what a pain! I knew the wired back of the switch would stick out a bit but wasn't expecting the holes to move.

(Click to enlarge)
 
#19 ·
Well, unfortunately the holes dont line up but it does work, its just loose and the retaining clip would be solid once the lock was bolted to the door...

But a bit risky to try in that fashion! :)


 
#21 ·
Andyman said:
Wak,

That cream coloured part of the original switch looks separate from the main body. Would it be possible to cut that off and Araldite it to the side of the replacement microswitch? Then you'd have a new switch which would fit the original holes.

Andy.
Its looks like it will prise away. I will take a better look tomorrow.

I think it may push through to the opposite side and then melted to make the 5mm flat on the opposite side. It should come off.

Only issue would be glue in the right place to make the switch work.
 
#22 ·
I wonder if when you prize it away you'll find switch mounting holes in the standard position (9.53mm centres)? In which case Anyman's idea might simply clip into the holes and provide location. The problem remains with rear clearance if you still use the bracket clamp. Perhaps the end of the bracket could be bent to lock it on in the slightly extended position?

The hoes through the switch would require M2.5 screws by the way (not M3 as I wrongly said). Drilling the lock body with 2.5mm holes might work but you'd have to watch breaking through into the 3mm holes already there. You could file slots out to the required position but that's getting fiddly considering repeat fixes in future.

Alternatively, a lever switch without the wire terminal cover would fit but you'd have to solder on and seal new wires yourself.
http://uk.farnell.com/jsp/endecaSearch/ ... 1851&N=401
 
#23 ·
John-H said:
I wonder if when you prize it away you'll find switch mounting holes in the standard position (9.53mm centres)? In which case Anyman's idea might simply clip into the holes and provide location. The problem remains with rear clearance if you still use the bracket clamp. Perhaps the end of the bracket could be bent to lock it on in the slightly extended position?
This is possible I was playing last night. I'll have a good look at the sides tonight and see whats under the oem plastic bits.
:)
 
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