Terminal A sunroof relay
09-26-2016, 12:45 PM
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09-26-2016, 12:47 PM
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06-06-2020, 01:11 PM
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This is how I tested by sunroof connections
I too was having a problem with my sunroof and read lots of forum posts and also the testing procedures at Clarks Garage. I also found that pin A of my sunroof relay was not getting 12 volts. I ended up spending lots of time trying to work out why and tracing connections which go back to the Speedo (and which would go to the cruise control but my car doesn’t have that).
I read somewhere that the sunroof has a safety feature whereby if you start driving the car with the sunroof released (i.e. with the arms fully retracted to the position where you can remove the sunroof) the arms automatically extend and lock the sunroof. My conclusion is that pin A is the one that takes the signal from the speedo / cruise control and causes the sunroof to lock in this scenario. I do not believe it is involved in normal operation of the sunroof.
So, I ignored pin A and spent my time understanding how the system worked, and by doing so I was able to get my sunroof working properly. Hoping it will be helpful to others, here’s how I checked my system.
My car is a 1987 951. It is European spec and right hand drive.
Sunroof switch connector. This is the switch for operating the sunroof in the centre console in front of the gear stick. Pin numbers here match the pin numbers in Clark’s Garage and on the circuit diagram.
Pin 1 (Blue/Green) : 12V when the ignition is in position 2 and 0V when in position 1
Pin 2 (Blue/Black) : 12V when the ignition is in position 1 and 0V when in position 2
Pin 3 (Green/Red) : 12V only when ignition is in position 2 and sunroof down switch is pressed
Pin 4 (Grey/Green & Yellow) : 12V only when ignition is in position 2 and sunroof up switch is pressed
Pin 5 (Grey/Black) : 12V only when ignition is in position 1 and sunroof down switch is pressed
Pin 6 (Black) : 12V only when ignition is in position 1 and sunroof up switch is pressed
The other place I checked was the connector in the trunk of the car, on the left side just above the sunroof motor . This is where all the wires described above go to. There is an 8 pin connector here. (It is shown on the circuit diagram at grid H38). I checked all the voltages here also. Here’s what you should find :-
Pin 1 : not connected
Pin 2 (Brown) : Negative - there should be negligible resistance between this and ground
Pin 7 (Red) : Permanent 12V – this is always live irrespective on the position of the ignition.
Pin 3 (Green/Red) : 12V only when ignition is in position 2 and sunroof down switch is pressed. This should cause the sunroof to lower.
Pin 4 (Grey/Green) : 12V only when ignition is in position 2 and sunroof up switch is pressed. This should cause the sunroof to rise, HOWEVER you should also find that Pin 8 (Yellow/Black) has 12V. If Pin 8 does not have 12V the sunroof will not rise.
Pin 5 (Grey/Black) : 12V only when ignition is in position 1 and sunroof DOWN switch is pressed. This should cause the sunroof to RISE, yes RISE ! HOWEVER, again, you should also find that Pin 8 (Yellow/Black) has 12V. If Pin 8 does not have 12V the sunroof will not rise.
Pin 6 (Black) : 12V only when ignition is in position 1 and sunroof UP switch is pressed. This should cause the sunroof arms to RELEASE. Yes the UP position causes the arms to RELEASE !
Pin 8 (Yellow) : I have described above when this should have 12V. This is connected to the microswitch that is in the roof at the front of the sunroof and this microswitch senses if the Sunroof is fitted or has been removed. This is discussed a lot in other forum posts. If this microswitch is broken then Pin 8 will never get power and the sunroof will not rise in either of the situations described above. This was the source of my problem. I have temporarily bypassed that microswitch until I can get a replacement.
There are other test procedures listed in Clarks Garage and these are very helpful and will allow you test the 2 microswitches on the front of the sunroof motor panel and the single microswitch on the back of it, and also the two relays at the base of the motor panel. Remember I am describing the later (1987 car).
Hopefully this will help someone and will save you spending the amount of time I had to spend to solve my problem.