And the most valuable tool when installing an alarm/remote start is a good multimeter and a computer safe test light/probe. My all time favorite is the PowerProbe III. Its a voltage meter and a computer safe test probe all in one. When you probe a wire, it not only tells you if its hot or negative, but how much voltage it has as well. It has plenty of other features as well that makes electrical troubleshooting a breeze. However, it connot take all the readings that a Multimeter can. It can only read voltage. You still need a meter to measure resistance and AC voltage (when testing the tach signal wire).