Car randomly will not start. Battery is good and starter was changed. No 12 volt cranking voltage at starter. No security lights flashing and a new key doesn’t fix the problem. Swapped starter relay didn’t fix either. How can I find out whats wrong? After 20 to 30 minutes, car will start again
Sounds like you got yourself a good one. Since you have a multi-meter to check voltage you can continue with that. This will narrow down the issue for sure. There is no battery voltage at the “S” terminal when it will not start. This is a great first step. Swapping out the starter relay is a great second step but don’t stop there. We need to make sure battery voltage is at the relay and that the relay is working and sending out voltage. Could be the shifter isn’t going all the way in park or the switch is worn. But testing will confirm the cause.
Testing the relay
You should see battery voltage at pin#3(brown/pink wire) and when activated(ignition key put in “START” position) you should see that voltage leaving the relay on pin#5(white/pink wire).
If this does not happen and you do have battery voltage at pin#3 then the next step is to check for battery positive and negative at pin #1 and #2. If no voltage is found then you need to trace from the PCM and from the park/neutral switch.
I will provide you with a wiring diagram of the starting system to help assist you.
Starting System Wiring Diagram 2005 Ford Five Hundred2005-ford-five-hundred-starting-circuit-1-of-1