try mo search sa internet "ampere draw test"
or follow these:

tester required:
DVMM (preffered) or 12V test light
disconnect neg bat terminal, wait for at least 20min (kung meron mga control modules ang car mo to put them on sleep mode). using the DVMM on ammeter mode (set mo nuna sa higher amp setting para hindi mo masira DVMM mo in case sobrang laki ng amp draw) connect mo yung isang lead sa battery terminal yung isa naman ay sa neg cable. continue trying hanggang sa milliamp range hangang makakuha ka ng reading (acceptable for some models is 5mA) kung mahigit 5mA (abnormal draw) then remove mo yung fuse one by one hanngang makita mo yung nag cause ng draw, repair the circuit that caused the draw. CAUTION: while in mA setting never kang mag "on" ng kahit anong system sa car or you'll say bye-bye sa DVMM mo.
or test light method, just same setting pag bright ang ilaw may malaking draw tanngal isa isa fuse hanggang mamatay ilaw test light.