Sunroof Arms Retract but do not extend

[Bulldog9]

Well, With the FPR/FPD all sorted out, finding a sunny day yesterday, I did what any enthusiastic new owner of a 944 would do, I removed the roof panel and went for a drive.

While retracting the arms for removal, I heard a crack from the drivers side arms, then the motor kept turning till I released the button. When I tried to re-extend the arms to lock the panel in, the passengers moved but not the drivers. So I retracted again and removed the panel and went on a 100 mile drive. Figured 'why not' Was fun while it lasted. A bit too chilly to go top off windows down, but still a great experience.

So I am guessing that I stripped a gear or broke a tooth on the extender arms. In addition, I am 99% sure that the two arms/cables are now out of sync.

Fun times all around!

[944 Ecology]

https://www.clarks-garage.com/shop-manual/body-03.htm

[Monkey Wrench]

Ive seen people take a little mold off those things and make a new one from the mold. maybe by pressing them into plasticine then using epoxy , or similar. Just in case it's hard to get. Nowadays someone can do it on a 3 d printer, maybe.

I was surprised how accurate they are, a friend made a little test piece where each adjoining part was linked together with tiny hinges and hinge pins. It did not snap together, it was made that way in layers, on the printer. pretty amazing.

[Bulldog9]

Thanks, I have looked at a few sites and I think it is the gear that moves the arm. I'm more worried about getting the cables and stops back in alignment. **It was working SOOOO nice before this.

I'll dig into it next week. SWMBO will be away and I will have more garage time.

[originalowner]

There are aftermarket brass gears available. Not sure of the downsides to that upgrade.

[Bulldog9]

Originally Posted by originalowner

There are aftermarket brass gears available. Not sure of the downsides to that upgrade.

I'll be using OEM plastic. Brass may not strip, but the Nylon gears are cheap and a designed in weak point. I am going to look into adjusting the clutch on the motor. I want to keep it as OEM as possibe, so I have New Porsche Gears on the way. I'll let the next guy worry about it when these nylon dry out in 20 + years

[TheSecondChris]

Originally Posted by Bulldog9

I'll be using OEM plastic. I'll let the next guy worry about it in 20 years

The motor is supposed to keep running, but there is a clutch inside that is designed to slip when the arms are fully retracted. What happens is that the clutch stops slipping where it should, and this strips the gears. If you have plastic gears, there isn't any damage and you just replace the gear. If you have a brass gear, the cable and arms can be damaged.

I'm glad I used plastic gears and also glad I had a couple extras when I rebuilt my sunroof mechanism since it took me a few tries to understand how it all worked and the only damage I did was to the plastic gears.

The way to adjust the motor so it slips is by turning a nut. You can find some decent videos on youtube. Tim Comeau CRE has a short one, and there is another one - I think it's MUNK's garage or something similar. There's another one made by a guy in the UK, I think.

[Monkey Wrench]

perhaps similar to the way a garage door works, if you stop them they have a little clutch like switch that turns the motor off, prevents it from destroying itself.

I guess in this case it;s just a spring loaded clutch that can slip and no power connection. - similar purpose.

it might look like a clutch disk and plate with a spring loaded washer, maybe an adjustment o get the right "squish" so the washer is putting the correct amount of force upon the clutch, enough so it works, but can slip if it needs to.

I imagine it might look like a bent spring steel washer that is flattened out against tension or a cup shaped washer. lubricating that area might make it slip?

[Bulldog9]

OK, new gears in, and cable/motor put in correct position. Checked microswitches, and adjusted the clutch on the motor. Down and Retract work fine, but Up and Extend do not.

Am going to check the Microswitch, then the actual Sunroof Switch. I initially thought the microswitches got goobered up when the gears broke and it pushed the cable into the trunk area, but puling it off the mounts and looking, that was unlikely.

**UPDATE:
- Checked Microswitch between visors for a click and there is one
- Pulled sunroof switch and is clean inside and has good function both directions
- Confirmed that the clutch is adjusted propery.

Everything worked fine until the gear in the drivers side lift stripped. With everything replaced, the arms will retract from fully UP (moved manually) and will stop in the locked position as it should. The arms also retract as they should to remove the roof panel, but The arms will NOT move in any of the 'LIFT' directions.

Any ideas?

[originalowner]

From Clark's...

[Bulldog9]

OK. First off.... SUCCESS!

Looks like it was Microswitch III, or a combination of dirty main switch, directional relays, and MS III.

But there is a story and some learning points. You'll have to read to the end for those...

I checked limit switches, sunroof control/console switch and micro switch by the visors according to Clarks. I also backed off the clutch in the motor so no more stripped gears.

I confirmed the function of all limit switches by manually turning the motor.

Bear with me as I sort through this torrid tale.

Manually, the sunroof raised, lowered, went into lock position, and arms retract with the microswitches clicking when they are supposed to. If manually raised, with key in the ON position, the motor will lower the sunroof and stop in the locked position, but it would NOT raise.

The same was true for the arm retraction. In accessory position, the arms will retract, but they will not extend.

Thinking it was one of the directional relays not reversing the polarity to the motor to raise, I swapped the relays hoping that the problem would be in reverse. No change.

So I decided to pull the directional relays, take them apart and check for function. I also cleaned the contacts and terminals with DEOXIT. I also pulled the Main Sunroof Relay and cleaned the connections. Not really needed, everything looked pristine.

Even though the switch 'tested' good with continuity, I thought that perhaps when lifting the sunroof more load was needed and there was some corrosion or varnish on the switch, I pulled it, pulled it apart, and used an emery board (sorry dear) lightly on all contacts cleaned with deoxit and reassembled.

Put it all together, and BAM........... The sucker worked!! ONCE............ Then it is back to lower and retract only...... So it is back to manual mode, crank it all the way to release, then to locked, checked to hear click from the limit switches I & II, then all the way to fully open. Hmmm..... No click from the Limit switch III. the slightest touch made it click. Seems that the mounting bolts were loose and allowed just enough movement to prevent contact. So I set it to guarantee engagement when fully open.

Specifics on testing.
1. Sunroof control switch - Works perfectly, good continuity in both directions.
2. Microswitch near visor - Works perfectly.
3. Limit Switch I - Worked as it should in all positions as indicated in picture below
4. Limit Switch II - Worked as it should in all positions as indicated in picture below
5. Limit Switch III - Worked, however it works OPPOSITE what Clarkes Diagram below says it should. **See PICS





Limit Switch III works the opposite from what is says in Clarkes Notes.

According to Clarkes, Limit Switch III uses terminal 1 and 2 and is supposed to be CLOSED when the Plastic cam thing rotates all the way around and depresses the limit switch in the OPEN sunroof position. However............... The actual situation (at least on my car) reveals that this switch works the opposite way.

When the switch is in "Sunroof open" position, and the micro switch is engaged, the limit switch reads OPEN... It reads closed in ALL other conditions (LOCKED and RELEASED). The mounting bolts loosened up and allowed the switch to move, and create the situation. Not sure if my 'gear shredding and cable overspill created the situation.

And THAT ladies and gentlemen is why the motor would not move in the FWD or UP direction. The Blackmagic electrical wizadry of the 944 Sunroof system needs the Limit switch III to be CLOSED in order to send power to the motor to move in the FWD (Going UP) direction.

This all started when after replacing the FPR I decided to go for a nice drive. I hadn't taken the roof panel off. When doing so, I heard a CRACK CRACK and the motor kept turning.

This is what I found when I first inspected........ 90% of the cable was in the trunk area.



My wife is away this weekend on a sisters ski trip, so I am babysitting the little living stuffed animal..... This thing is so needy. At least my shepherd used to be able to get a beer from the fridge. This thing? Not so much ;-)



The thing that started this mess is old nylon gears and a clutch on the sunroof motor that tightens over time. In order to adjust, you need a THIN wrench to hold the adjustment nut. Thankfully, I had a very thin 13mm wrench in the stash from my grandfathers toolbox. I backed the nut off 1/2 a turn. There is a Torque spec'd number, but I just went by feel. Now when the motor is in 'retract mode' the motor just happily spins when the arms are fully retracted.


This was the drivers side Gear......... Passenger was mostly good, 1-3 gears stripped.


OK, you've read this far. Here are MY learning points.

1. Clarkes Garage has errors. The Limit switch III when depressed (sunroof in open position) is open, and reads closed in all other conditions. Clarkes has it opposite.
2. Give the system time to react to changes. Wait 2-3 seconds before changing direction. I was clicking Up/Down, Lift/Lower faster than the system liked.
3. Loosen the clutch on the motor BEFORE it shreds your Sunroof Lift Arm gears.
4. CHECK that the limit switches are not loose. Had I done this FIRST, it would have saved me hours of diagnosis.
5. The engineers behind this system sold their souls to the devil...............


All kidding aside, this was a great learning experience. Best part was THIS unexpected refresh cost was only $30!