Many electrical components on a car are controlled by computer...but not directly! The computer uses an electronic switch called a relay to do the dirty work. So, if there is a problem with the primary component (fuel pump, a/c compressor clutch, cooling fan, etc), you first have to figure out which of two circuits has a problem; the one that uses the relay as the switch or the one that actually turns the relay on or off.

The uActivate circuit tester is placed in the circuits in place of the relay and allows easy access to both sides of the circuit. You can use the tool to perform voltage and resistance tests, measure current flow, manually operate the primary component and even perform a voltage drop test on the relay control circuit.

For more info, visit http://www.aeswave.com. Click this link to subscribe to Motor Age! http://bit.ly/MA_YT_freesub