Sunroof oddities

[zcacogp]

Chaps,

A slightly odd one. I'm throwing it in here more out of hope than expectation ...

The sunroof on my S2 is misbehaving. I have tried smacking its bottom and putting it on the naughty step, but it hasn't helped.

It won't open. Reliably. Sometimes it won't open at all (press the button and nothing happens - no spinning from the motor, nothing). Sometimes it will open a little, but stop half-way. Sometimes it will not open, but will open if you try it a couple of minutes later. Sometimes it will open a little, and if you release and re-press the button it will open fully.

It will always close properly, when required.

My guess is either an intermittent bad connection, or something rum is happening with the microswitches. Either way, I need to take it apart and diagnose it properly. Probably with a wiring diagram in my hand. (And - thankfully - it's not a major fault, neither is it likely to be difficult or expensive to fix, I am hoping.) But has anyone seen this problem before, and therefore have suggestions as to what is (or isn't) happening?

All suggestions welcomed - thanks.


Oli.

 

[JamesO]

Have you tried shouting at it? It helps with my randomly sulky rear wiper, that and the threat to remove it.

 

[Eldavo]

Check that the centre tab at the front is pressing in the electrical interconnect switch properly. This was the source of much head scratching for me and a simple poke sorted it out.

 

[xenon]

Sounds like the switch.

 

[Diver944]

ORIGINAL: Eldavo

Check that the centre tab at the front is pressing in the electrical interconnect switch properly.

I reckon Eldavo is spot on the money. That front microswitch detects if the sunroof is there in the first place.

www.clarks-garage.com has a really good write up covering all aspects of the sunroof if its something else

 

[zcacogp]

Chaps,

GREAT suggestion - front microswitch. Thanks. Not one I would have thought of at all. If the tab isn't pushing it correctly (or there is a bad connection there) then I guess it probably would produce all those symptoms.

Nice and easy to check as well. Thanks Eldavo and Paul. In fact, it's so easy to check I may have a quick gander this evening after work (one of the joys of BST being that there is a bit of daylight when you get home from work.)

Why would the tab not push the switch properly? Does the tab move out of alignment, or does the switch move away from the tab?


Oli.

 

[xenon]

ORIGINAL: zcacogp

Thanks Eldavo and Paul.

ohh, it's just as well I'm not easily offended. [8D]

 

[zcacogp]

Ian,

I'm holding your suggestion in the back of my mind (it was my first thought as well, so great minds clearly think alike.) If it turns out that you were right then I'll come back on here and publically acknowledge you as being the guru of all things 944-sunroof-esque and in possession of a brain bigger than the average planet. I'll even buy a large box of Thorntons chocolates specially to say 'Thank you' (although I may snaffle half of them as it was my idea as well ... ) []


Oli.

ETA: And I'll promise never to call you Mr Picky again. How's that for a deal?

 

[pegasus]

Hi Oli, I was lucky with mine that the switch was stuck in the on position,everything worked but when the sunroof was out the horns/arms that locate in and adjust the sunroof could still be moved in and out,when the roof panel is out the switck should be in the off position and nothing works until the roof panel is re-fitted. I found that the plastic holder that the microswitch fits in had one of the microswitch locating tabs damaged which let the microswitch tip to one side and jam (in the on position). later I found that the indi garage that fitted a new sunroof motor three months before I bought the car had not tightened the two rear motor micro switches another two minute job that could have been easily avoided,all the best John.

 

[xenon]

ORIGINAL: zcacogp

Ian,

I'm holding your suggestion in the back of my mind (it was my first thought as well, so great minds clearly think alike.) If it turns out that you were right then I'll come back on here and publically acknowledge you as being the guru of all things 944-sunroof-esque and in possession of a brain bigger than the average planet. I'll even buy a large box of Thorntons chocolates specially to say 'Thank you' (although I may snaffle half of them as it was my idea as well ... ) []


Oli.

ETA: And I'll promise never to call you Mr Picky again. How's that for a deal?

Agreed. Although it does sound more like the front microswitch as advocated by our learned friends.

 

[zcacogp]

Ian,

OK, being serious for all of 30 seconds (I type fast). I mis-read your post as referring to the dashboard switch, not the one in the roof.

Apologies. And thanks for the suggestion.


Oli.

 

[xenon]

I was referring to the dashboard switch if it's only problematic in one direction, but it could be either from what's been said.

Good luck and report back.

 

[zcacogp]

I thought so ... I hereby retract my apology then! []


Oli.

 

[zcacogp]

OK, top marks to Eldavo and Mr Smith for their internet-diagnoses, and no Thorntons for Ian (sorry Ian!)

If you push the little switch at the front of the sunroof in with a screwdriver it works perfectly. Every time. If you release the switch while the sunroof is opening, it stops opening.

Ergo, it's the switch. (Interestingly, if you hold the switch in, the sunroof opens wider than I have ever seen it open before, suggesting that the switch has never worked quite as it should.)

I'm not sure what has changed. Either the finger on the front of the sunroof has become slightly bent (I doubt it, it's heavily made), or the switch has moved. Or possibly the sunroof has somehow 'settled' in the aperture, such that it no longer pushes the switch as much as it used to.

What do I do to fix it? Bend the finger or move the switch? A brief look hasn't revealed how the switch is held in ... I'll consult the manual and see if I can take it out, and whether that tells me anything useful.

Thanks for your suggestions. I would have been (wrongly) removing the rocker switch in the dashboard and probably the motor as well had you two not come up with the right suggestion. That's saved a lot of time.


Oli.

 

[zcacogp]

Another question.

Presuming that the switch at the front of the sunroof is working as it should, what stops the sunroof from opening beyond the maximum position? Is it one of the switches on the motor, or is it the switch in the roof?

(In other words, do I need to adjust the roof switch such that it breaks the circuit when the roof is fully open, thus limiting the travel, or does something else do this?)

I am suspecting that something else does this, as when I keep the switch pressed all the way in with a screwdriver the roof stops moving at a suitable position. Also the 944 manual doesn't seem to suggest that the roof switch needs adjusting.


Oli.

 

[pauljmcnulty]

Presuming that the switch at the front of the sunroof is working as it should, what stops the sunroof from opening beyond the maximum position? Is it one of the switches on the motor, or is it the switch in the roof?

The front switch is there so the system knows the roof is in properly. The arms are controlled by the limit switches on the motor itself.

 

[pegasus]

As paul says and I explained earlier the switch is made when the sunroof is put in place and goes open circuit when the roof is removed,If the switch sticks in the made position you will have everything work including the locating arms coming out to locate the roof even though it is not there,the reason for the switch is to stop the arms locating if you press the sunroof switch with no panel in place,unfortunately if it sticks in the open circuit mode it assumes that the sunroof is not in place and nothing works,as I said it is worth checking that the two limit switches are both mounted tightly, when you look in ther you can see the operation of the whole system, John.

 

[zcacogp]

Thanks chaps.

John, Sorry, didn't mean to ignore you. Just wanted to be sure that the roof switch is only to denote presence of the roof and nothing more. When you talk about the two limit switches being tight I presume you mean the ones on the motor, in the boot?


Oli.

 

[pegasus]

Yes I found that both switches on the motor in the boot were slack,it was only a matter of tightening the screws but if you have a look in there you will see how it all works and check the clutch tension, it tends to tighten over age and if you take the sunroof out,when the arm retract to the body there is no stop switch the motor keeps turning and the clutch slips,if the clutch slips at too high a torque it strips the teeth on the plastc gear cogs,some would say they are a bad design but they serve their purpose as mechanical fuses if you like,all the best John.

 

[zcacogp]

John,

Thanks. I'm pretty au fait with the mechanical workings of the sunroof; I've been there, done that and bought the T-shirt as far as the gearwheels go. They are indeed easily stripped when the clutch is forced to slip when the legs are retracted, and the clutch always transmits more torque on a hot day (I'm not sure why, I think it may be to do with the expansion of the clutch plates, but am not 100% on that.) Hence a lot of sunroof gears go pop in the middle of summer - mine did. Twice. I now have the clutch set loose - loose to the point that it only just manages to move the roof, and sometimes the panel needs a bit of a push to help it on it's way. A pain perhaps, but it will hopefully preserve the gears better.

The mechanism in the boot is enormously primate but quite simple, and does the job. I'm sure no modern car would have such a bit of engineering tho' - it's heavy and cumbersome, and must be expensive in terms of manufacturing costs. The switches as part of the control mechanism were the only bit that I never fully investigated ... until now!

Out of interest, what were the symptoms of the switches on the motor being loose? I'd guess that the roof didn't behave consistently; the stopping points (for up and down) changed as the switches moved - non?


Oli.