blower motor resistor on 1998 Nissan Frontier

where is it located and how difficult is it to replace.
fan motor runs

Asked by for the 1998 Nissan Frontier
what is problem if fan works
1,2,3 setting dont work at all. 4 is intermittent. The vents all change fine and the heat adjustment changes fine. Its the motor speeds that dont function properly
1 more answer
i had the same problem there is a pcb board under the dash that needs to be replace. i got it at the dealer for 75.00 bucks.