I have an 02 stock civic and the blower motor stopped working. I check the all the fuses and they are good. So i did the test thing and got a error 12 which means blower circuitry. I took the blower motor out and tested on my on ps and it worked great so it's not the motor. I then connected the motor back to the car but i connected the ground of the motor to a bolt on my car and the motor worked but only on the highest setting and i could turn the ac on/off. Do you think i have a bad ground connection somewhere? Could the relay by the motor be bad or is there some kind of a resistor that i should know about?
Thanks, any reply is helpful

 

Yeah, test the power transistor:

 

There is diy written about this on another site. Look here:

http://honda-tech.com/zerothread/2082345

The resistor pack (on older models) on the blower motor can burn out some resistors and leave you with only the highest speed on the blower motor. you will need to replace just the resistor pack though in this case, it looks like you have a power transistor and no resistor pack at all.

At least through the diagnostic test posted by RonJ, you should know right away if the power transistor is good or not.

It looks like you did some good troubleshooting to demonstrate the fact that the blower motor is functioning properly. that's a great job.