Heater/AC fan control 1999 EX

[Kennyj]

My heater /ac fan control now only works on off and full speed. Do I need to replace the entire control panel or is this an issue with the fan motor??
Thanks in advance for any info

[thud105]

I think your blower "power transistor" is defective. It controls all fan speeds except for Off and HIGH. See below for an explanation on how the bower circuit works. I found a transistor for my 03 CR-V at Advance auto, it's an easy DIY replacement. Also clean your cabin air filter... that's what kills transistors, they overheat when the airflow is restricted.

The blower motor is controlled by the heater control panel which receives battery voltage at all times through fuse 47. With the ignition switch in ON (II), battery voltage is supplied to the control panel through fuse 17. The control panel is grounded at G401. Battery voltage is applied through fuse 55 to the blower motor relay contacts at all times. With the ignition switch in ON (ll), the blower motor relay is energized and battery voltage is supplied to the blower motor. The blower power transistor controls the blower motor in all speeds except HIGH. The blower power transistor is controlled by the heater control panel. When the heater control panel requests HIGH blower speed, it grounds the blower motor HIGH relay coil, the relay is energized, which connects the blower motor directly to ground, making the blower run at high speed.