You can divide the system into four parts, and each one can be tested at the starter relay socket. You can use a test light or a digital voltmeter. Ground the test light or voltmeter, then probe the four terminals in the socket. (Disregard the unused one in the middle). One must have battery voltage all the time. If not, check the wire going back to the battery positive. One must have battery voltage when you turn the ignition switch to "crank". If it does not, check the ignition switch and the terminals in its electrical connector.
Now move your test light or voltmeter ground wire to the battery positive post because we'll be looking for a ground path at the two remaining terminals. You should read battery voltage, (negative, but that's irrelevant), or the test light should be bright on the two remaining terminals. If only one of the two shows a good ground path, put the shifter in "reverse" or "drive". If the voltage goes away, that is the neutral safety switch circuit and it is working. If the voltage stays there, that is the starter solenoid wire and it is good. Troubleshoot the circuit with no continuity to ground.
Those four measurements will work on any starter relay, however, if you have a manual transmission there will be a clutch switch in the same circuit as the ignition switch. You should still have battery voltage on one terminal when the ignition switch is in the "crank" position but you'll have to press the clutch pedal at the same time. Also, there will just be a ground wire instead of a neutral safety switch but you still should find two wires that read to ground when the tester's ground lead is on the battery's positive post.
Sunday, November 25th, 2012 AT 10:09 PM