P reg Daf 45 150 whats another solenoid on below stop solenoid?

I had problems to start my -97 Daf 45 150 horse box. It's always been excellent starter. I did trip to Finland and on my way back it started really giving problems to start it. Drove well but it took some cranking over to get it started. Both filters changed and were pretty bad. Got better but still not right. Did try stop solenoid plunger out and still not perfect like used to. There is another solenoid below stop one. What is that solenoid for. By the way, it stopped ok from key even plunger was out. Thanks Olli