940 non turbo

I was checking around for electrical fault as my car continues to have bad idling, especially in the morning, after the engine has been shut down for several hours.
In the process, I removed both wire connectors from the ignition coil but did not note which wire goes to which terminal.

When putting the wires back, I tried it both ways and car seems to run okay with wires red/white to positive or to negative. Similarly for the blue wire when fixed on the positive or negative terminal. The terminals are marked 1 and 15 at the side.

What is the correct terminal for the red/white wire and the blue wire?

Will the car or ECU suffers any irreversible damage with the wires put wrongly. I've ran my cars for several days in either connection.

Please advise and thanks in advance

Laozong