Sunroof Mystery

[chrisjcoe]

Hi all

Twice now, when it's been very hot and I've had the sunroof out, the arms have refused to extend to lock it back into place when put back in. The motor works, I can hear it, but the little locking arms just don't move. The first time I waited a few hours until the world cooled down a bit and tried again, success. The second time (a few weeks ago) I tried regularly for 2 days but had no joy, the motor whirred away but nothing moved.

I have been reluctant to use the car since with an unlocked sunroof, but finally decide to take it to work today without checking the forecast, mainly due to the upcoming Helmingham show on Sunday. When driving in I could hear a few whirs from the back and thought that perhaps my dead rear window wiper motor was trying to contact me from beyond the grave. I checked about to find the rear wiper switch, tried a few things, but couldn't work out where it should be. Then I glanced up and noticed the roof was locked in place. This has pleased me due to the near constant rain so far today.

Now I haven't tried to lock it for a few weeks, and the last time I looked (a few days after they were stuck in the release position) they were still down. I can only assume that something triggered them to extend this morning.

Anyway, my initial assumption was that the cogs had been stripped, but the fact they are now extended tells me it is all in mechanically working order. So does anyone know why the roof arms would refuse to move one day, but then work find days later? Heat is the common factor hear, so what could a hot day do that would stop them working?

For those who would rather I hadn't removed the intentional and unintentional innuendos from the above, I will happily post a shortened summary....

Thanks

Chris

 

[ChasR]

Silly question, but whilst the motors etc. can be heard, did you try locking the sunroof with the ignition at position one? Even coming back to 944 ownership this confused me (the direction arrows didn't seem to make much sense!). The arms lock when you lock the car, which could be what caused them to go up.

Failing that, I would be looking at a microswitch issue.

 

[chrisjcoe]

Thanks for the advice. Yes, I did have the key in the right position. It took me a little while of ownership before I found that little bit of information out though, so understand that others may not know the magic.

 

[pauljmcnulty]

Mine was tthe microswitch at the front. Simply wiggling it a bit worked for me, although I'd bet it'll go again and I'll need to clean it up and bend it back in to shape a bit.

 

[chrisjcoe]

Thanks Paul. Was that on the actual console switch? If so, I could hear the motor moving behind me when I pressed the switch, so assumed the switch is ok

 

[pauljmcnulty]

ORIGINAL: chrisjcoe

Thanks Paul. Was that on the actual console switch? If so, I could hear the motor moving behind me when I pressed the switch, so assumed the switch is ok

No, it's the switch in the roof that senses when you've replaced the panel. The contact gets bent, so it doesn't recognise that the sunroof is in and it should lock it. It's above the interior light, by the triangular metal thing.

 

[zcacogp]

Funny. A heat-related sunroof issue. I have had a small theory on this for some time. Your post is interesting.

As you know, there is a small clutch by the sunroof motor which slips if too much torque is put through the system. This is meant to be set such that it slips before anything breaks, but the adjustment is usually slightly out so the sunroof cogs strip. I always keep the clutch on mine very loose for this reason - to protect the cogs.

However, on the two occasions the cogs have gone, it has been a very very hot day. Leading me to surmise that the clutch grips harder than usual on a hot day, and hence transmits more torque. Your symptoms suggest the opposite - that the clutch slips on a hot day, and doesn't transmit enough force to move the legs at all.

Either way, it seems that temperature has an effect on the operation of the clutch.


Oli.

 

[chrisjcoe]

No, it's the switch in the roof that senses when you've replaced the panel. The contact gets bent, so it doesn't recognise that the sunroof is in and it should lock it. It's above the interior light, by the triangular metal thing.

I'll add this to list of things to check when I get round (soon) to sorting it!

Your symptoms suggest the opposite - that the clutch slips on a hot day, and doesn't transmit enough force to move the legs at all.

Another thing to check! I was going to expose the motor and get my girlfriend to operate the switch (she gets the exciting jobs) while I see what happens. Sods law means it will work perfectly every time we try though.

 

[zcacogp]

ORIGINAL: chrisjcoe

No, it's the switch in the roof that senses when you've replaced the panel. The contact gets bent, so it doesn't recognise that the sunroof is in and it should lock it. It's above the interior light, by the triangular metal thing.

I'll add this to list of things to check when I get round (soon) to sorting it!

Your symptoms suggest the opposite - that the clutch slips on a hot day, and doesn't transmit enough force to move the legs at all.

Another thing to check! I was going to expose the motor and get my girlfriend to operate the switch (she gets the exciting jobs) while I see what happens. Sods law means it will work perfectly every time we try though.

Try that switch in the roof as McNulters suggests first, but if the motor was working then it suggests that the switch is signalling it OK.

It can be worth watching the sunroof motor working while someone else pushes the switch as it's quite informative about the way the whole thing works. While you are there you can adjust the clutch too - aim for looser rather than tighter ...


Oli.