Sunroof operation. Electrical gremlins?

944 S2 · 05-06-2019, 06:21 PM

I’ve notice my sunroof on my S2 only want to work when it feels like it. I’ve taken the switch apart and cleaned the contacts (this time without dielectric grease!).
Any thoughts on intermittent function? Could it be related to an ignition switch going bad? Have thought about replacing it since they seem to have a limited life.

racer · 05-07-2019, 04:32 AM

Which switch?

theer · theer's Garage

Yes, which switch? There are a bunch that play a role: ignition, console, limit switches on the motor assembly. Plan to spend some quality time getting to know the wiring diagram.

Check the micro-switch at the front of the sunroof opening and make sure you are getting good and consistent contact.

944 S2 · 05-07-2019, 05:39 AM

Sorry, let me clarify. I’m talking about the sunroof switch in the center console to open and close the sunroof.

I wouldn’t think the limit switches play a role to initially open the roof right?

universeman · universeman's Garage

The limit switch in the front center of the opening tells the car whether or not the roof is closed - could be part of the problem. I doubt the ones in the rear compartment by the motor would affect you, but they could. Use an DMM and probe the contacts in the switch and the motor and make sure you're getting 12v everywhere you should (into and out of the switch...) that's where I'd start.

Geoman · Geoman's Garage

I just went through a similar issue with my sunroof. My console switch was fine. Do check continuity on the microswitches that reside on the motor. They are connected to the console switch so if one of these switches is not electrically intact, then the console switch won't work. At least that's what the wiring diagram says for my 924s. I replaced both switches and the console switch worked fine.

944 S2 · 05-07-2019, 07:18 AM

3 limit switches in the back by the motor on late models cars right? I don’t think there are any in the roof.

racer · 05-07-2019, 07:34 AM

fwiw, my intermittent issues were fixed by replacing the micro switch at the front of the sunroof (just above the rear view mirror, if you will). That's why I asked "which switch" as there is more than one.

Geoman · Geoman's Garage

Yes, 3 on the motor assembly. One is on the back side...have to remove the assembly (3 nuts) to get to it, but I would check the two on the front first. There is the 4th switch as Racer mentioned between the visors and behind a plastic cover. Need to remove the roof to get at it. When the roof is removed, simply push that plastic cover and you should here the switch click on and off. If you do that's a good sign, it doesn't mean there is continuity in the switch, but I would wait on going further with that switch....in my opinion....because that plastic cover needs to be gently! pried off. There are two small plastic "hooks" on the back of that cover that snap into place and I bet breaking them is not hard to do!

I would check the switches AND the relays on the motor assembly first. Clark's Garage write up is very useful with this.

Redmacklin · 06-01-2019, 05:38 PM

I have an electrical problem with my sunroof. I have no power to any of the terminals that connect to the main switch. SO that means that power must not becoming from the relay. but the instructions from Clark's Garage, do not match my relay at all. My car is a 968 not a 944. Does anyone know which terminals I should be checking with the relay? I opened the relay and I could see no breaks or cracks anywhere. It looked brand new inside.
Dwight Anderson
94 968 coupe