hi my 2003 civics heater went out. in the summer it used to work sometimes on rare ocaasions. the ac also doesnt work.is it the blower motor? or the transistor?thanks!

 

If you're talking about the interior fan not working, usually it is the transistor.

Check if power is reaching the motor first though. Power on both wires to the motor is almost certainly a bad transistor. Power across the motor (one wire live, other one grounded) is a bad motor. Both wires at zero volts check the fuse and relay under the hood. Do these tests with the key on and the switch at high speed.