Thank you every one for your help. I finally found that the transistor was faulty.

So I purchased a new transistor form Honda e-store part number: 79330-S5A-942.

 

I piggybacking on this thread. My 02 Civic Si is doing the same thing (DTC 12 etc.). Can I test the power transistor (as described in the manual) with the battery still connected but with the harnesses disconnected (not battery power going to it)? Also, I assume I can remove the power transistor and have the car still function (minus the blower fan of course).

I don't have my radio code and don't want to spend the $50 to have the dealer find it for me.

 

Yes to both.

 

OK, I went to the dealer to have the power transistor tested. The mechanic said that the power transistor would likely pass OK (test for 1.4-1.5 ohms), but should still be replaced. His experience had been that the transistor typically tested OK and the problem persisted. Once replacing the transistor, the problem went away. He also suggested I supply power to the blower motor to see if it works properly. He said simply go around the transistor by taking the harness and jumping the two "fat" wires. If the fan works, then the transistor is the problem.

And to prove the mechanic right (or perhaps it's just luck), I took the transistor to Auto Zone and it tested 1.476 ohms. Go figure.

Does that sound right?

Should I just pull the trigger on the transistor?

Thanks
Russ

 

The transistor is fine. Follow the troubleshooting steps in the diagrams to locate the problem.

 

I did the second test on the power transistor and it tested OK. Now I'm back checking out the circuits. I've tested the blower motor (steps 2-4 of DTC #12) and it comes on bull blast.

I don't have a continuity tester, so I'm skipping to steps 8 through 11 (at least those are the numbers in the 2002 Civic Si manual). I'll report back.

One silly question though. If the blower motor was bad, would I ever get it to work in these test scenarios? I thought once the motor was fried (internally), it'd never come back on. In some of these test, the blower is working just fine.

 

Buy a $15-$20 digital multimeter so that you can test for continuity and voltage in the circuit.

The blower motor is fine.

 

I got a NO on step #9 - Repair open in wire between the power transistor and the blower motor.

Uh, I'm at a loss now.

 

Motors may become intermittent before they completely quit. If you ever measure 12 volts between the terminals at the motor and it is not running, the motor is bad.

Like Ron said, get yourself a volt-ohm meter since your eyes can't see electricity, you're working blind trying to do any electrical diagnosis.

 

Thanks guys. I'll pick up a volt meter at Harbor Freight.

Thanks
Russ