2001 S60 T5 - Manual Shift

Hello:

I have a 2001 Volvo S60 T5 Manual Transmission, and I have about four questions that I need help with:

1. I have a 2001 S60 T5 and I am having cruise control issues. What is happening is that sometimes when I start my car and need to activate the cruise control it works perfectly fine, and then there are times that the cruise light will not come on when I engage the steering wheel switch? What I tried today was when the cruse did not engage I stopped the car, turned off the ignition and restarted the car the cruise worked fine, but this condition is getting worse. I think this is a sign that my cruise control system is failing. Does anyone have any ideas how to correct or fix this problem?

2. I was wondering if it is required to change oil in a manual gear box, if so what the frequency, and does the trans axle need to have oild changed?

3. I need to replace my 2001 Volvo S60 T5 Serpentine Belt and I was wondering if there is a video to watch or can someone describe to me what need to be done?

4. I was wondering if it is required to change oil in a manual gear box, if so what the frequency, and does the trans axle need to have oild changed?

Thanks for anyone's help.

Lobo1943