My honda SM4's blower fan motor has a resistance of 0.8 ?, & mostly us ed @ 7½ v when alternator @ idle rpm produces 13½ v, i.e. 6v is w asted as heat by these resistors which presumably have a total resistance o f 6 ÷ 7½ x 0.8 ? = 0.64 ?, i.e. # of watts wast ed must be 6v x 6v ÷ 0.64 ? = 56¼ watt. In Dec'12 I noticed a Mercedes 350 has the same problem ( like cheaper cars have ) of heat inside users' space when aircon is off, i.e. no buck conver ter is used to reduce blower fan motor's voltage, so these resistors heat u p this space even after aircon is switched off. Does any car maker use a buck converter to reduce this voltage ? Does any1 know where I can buy a buck converter with easily switchable output voltag es of 4, 6, 9 & 12 v, of ( 12 ÷ 0.8 ? = ) 15 amp, to replace these wasteful resistors ?
- posted
9 years ago