Today we are working on a 2001 Honda Civic. The customer came in stating his turn signals don't work and his heater fan is out, as well. After explaining what we may be looking for, he agreed to leave the car with us to diagnose it. Now, Electrical problems can be very complicated. Just looking at all the wires can set anyone's head spinning. Trying to find something you can't see....electricity...and understanding how all the parts relate one another takes a cool head and a clear mind. Fortunately, the turn signal switch was obviously broken. the normal "click", up or down would not produce the wanted "blink". Push a little harder and it would start to work, let off and it would stop. Ok, got that one... Next up, the heater fan...not so easy. After checking the fuse and the relay for power (good), we checked for power down at the fan itself. Ok, we have power there...next to check was the resistor. This is the thingy that tells the fan how fast to go. It's a variable resistor that adjusts how much power the fan gets. The more power you give it, the faster it spins.