On last Thursday and today, my A/C and heat stopped blowing intermittently in my 2000 Civic EX. (It also stopped blowing intermittently when I used the fan only and did not engage the A/C button.) The A/C and heat started blowing fine again after leaving them off from 1-2 minutes at most.

I saw a DTC chart in another thread of a 2002 owner with a similar issue.

Does anyone know if I can use this same DTC chart for my 2000 model to pinpoint the issue? Attached is a pic of that chart and what my climate control buttons look like.

Your help is appreciated. Thanks!

 

It's usually the power transistor though it could be the motor. The self test will not diagnose between the two, you just get a code 12. While it is turned on but not working, measure the voltage at the motor between the two motor pins with the motor plugged in. If you have 12 volts between the pins but the motor doesn't run, it's a bad motor. If not, measure from each pin to ground. Getting 12 volts on both pins means it's a bad power transistor. Some parts stores call it the "resistor". If you have zero volts from both pins to ground, check the fuse and relay under the hood.

 

Thanks mk378.