my 1999 2 door rav heater blows cold air. on 1999 Toyota RAV4

my '99 rav was shipped from guam and the heater was never used. we moved stateside and now the heater just blows cold air. please advise on what i need to do.

Asked by for the 1999 Toyota RAV4
check your heater core hoses, maybe someone bypassed the hose or never have heater core.