Where can I access a starter/ignition switch wiring schematic? I've searched this site and cannot find one. I am still having an intermittent no-crank condition. I have low voltage (7 volts, but when cranking, it has about 10 volts) on the purple wire at the starter. I've checked the battery and both cables. Replaced the starter and ignition switch and bypassed the neutral switch. No help. Do you guys know of a common problem I should look at? Thanks for your time.
Terry
Ideally get a diagram out of a factory shop manual. Also watch out for any service bulletins that may have been performed on your car.
Basically you have 12V coming out of the battery going through a fusible link wire to a junction stud on the backside of the radiator support. From there a wire then goes into a loom with inside the loom has a splice in it to allow extra legs or wires to come out with one wire going to the horn relay bus (and the other leg goes to the output post of the alternator and the last leg to the external voltage regulator which in your case are in no need to be concerned about).
On the horn relay bus there is another wire connected to it and this wire then goes to and through the firewall bulkhead connector and then once inside this wire then gets split again with a wire going to the ignition switch (and another leg going to the fuse block and another to the headlight switch but here again too, should not be of concern with your issue).
Now out of the ignition switch is the crank wire and depending on the car, there may or may not be a safety switch and regardless if there is a switch,power needs to pass through it and then back out of the firewall bulkhead connector to where back in the engine compartment this wire then goes down to the starter solenoid.
As you can see there are a few connections between the battery and the starter solenoid so I would get out your voltmeter and start at the battery with tests with the car off then cranking and then work your way through the circuit ending up at the starter solenoid.
You will notice a little drop the further you get away from the battery and this is normal and could add up to enough to prevent a no crank situation but there might be a spot or two the voltage really drops and then I would concentrate in those area's to find the issues.
Also too, reference your meters ground to one point such as the battery. Moving the ground from the battery for one test and then grounding it to a spot under the dash may show a voltage drop but it could be on the ground side.This is why it's important to keep the ground in one spot like the battery.
Oh, and so you know, intermittent issues can be a bear to trace down some times.
Jim