POWER PROBE III
An amazing tool to test electrical systems and components, circuits. (click on the picture for link to demonstration). I've had it for years and solved many electrical problems. Fuses, relays. It can provide 12 power to parts such as lights, power windows, wiper motors. Continuity. Tell you if the wire carries ohms, if the voltage is + or -.
A must have tool is you want to diagnose automotive electrical. This video doesn't even begin to show all the stuff it can do. I mean fuses, lights, volts, continuity.
Does anyone remember the Ford/Mercury's with the keypad door locks? Had a Lincoln Town Car lockout, knew the code but battery was dead. Can't open the hood to jump. I plugged the power probe into the lighter plug on my jump start box. Slid under the car far enough to reach the starter. Hooked the little clip to the starter case, put the end of the probe to the battery cable terminal to the starter. Pushed the 12v button. Owner punched in the door code. Door locks opened.
Understanding how a power window works makes testing motors easy. It only has 2 wires on the motor. What make it go up and down is by switching polarity. And the pp3 has the alligator clip on a separate lead plus the metal probe. hook up one to each lead. Then you can push the top of the button to send 12v through probe tip and negative to the clip. If you push the bottom of the switch it reverses the polarity! It goes up or down.