Nobody uses the word "Salam" in greeting one another in Malaysia, not even locals. You would get pretty strange looks if you do.
If you want to be friendly, just say "Apa khabar?" which means "How are you". They will reply "khabar baik" or "baik" - which means "i'm fine / good".
Go the extra mile then, and say "Sudah makan?" i.e. "Have you eaten?" to which they will reply "sudah" - yes or "belum" - no. You know..... food is an important preoccupation to us Asians