1990 300e problems

[etowncd]

Hi

I just bought a 1990 Mercedes 300e and have a few problems that i'm hoping i can get some help with.

1)The heater control does not light up....is there a bulb i can replace?

2)The Cruise Control disengages after being set. You can set it again and it works for a little while then disengages. It always sets and then disengages after about 30 seconds of driving......any ideas???

3)The idle is smooth about 750 when in park but when its in gear and you come to a complete stop it feels rough....the idle stays around 500-600 but it feels rough like it wants to move. any ideas???

Hope somebody can help.
THanks in advance for all the help.