E150 won't crank over

[KtoddSacto]

Have a 2000 E150, the starter was inconsistant for a couple months. Seemed when it was hot it would not start. Now it wouldn't start at all, but was able to jump at starter. Replaced starter, but still will not turn over. My understanding is that the solenoid and regulator are on starter. Any other ideas?

[Selectron]

Hi, welcome to the forum. I'm not familiar with your vehicle but I had a look at the wiring diagram for it, and while you're correct in saying the solenoid is mounted to the starter motor body, there's also a starter relay prior to that. It's likely bolted onto the fender or firewall, and although Ford refer to it as the starter motor relay, it's also commonly known as the fender solenoid or firewall solenoid - the different terms all refer to the same part though.

Your van appears to use the three-terminal type, which will have two large terminals with heavy cables attached, and a smaller terminal with a correspondingly smaller wire. They don't cost much, so you might just want to pick up a new one and fit it.

Replacing the relay might not fix the fault though because it could also be a problem with the ignition switch 'Start' contacts, or the transmission range sensor (allows the engine to start only when in Park or Neutral).

When you turn the ignition switch to the Start position, current flows through the 'Start' contacts and then on through the transmission range sensor contacts, and if that path is intact then 12V will be applied to the small terminal at the starter relay. That creates a magnetic field within the relay which causes a plunger to move and bridge the two larger terminals - current then flows to the starter motor solenoid, and the starter motor will crank the engine.

First check then would be to see if 12V is arriving at the small terminal on the starter relay when the ignition is switched to the Start position. The wire on that terminal should be red/light blue, and you can check for 12V with a multimeter, or use a 12V test lamp. If 12V isn't arriving then that indicates a problem with the ignition switch or transmission range sensor. If on the other hand 12V is arriving, then that indicates a problem with the starter relay or its connections, so ensure the connections are clean and secure, and if it still doesn't crank then replace the relay. You should also check that the battery connections are clean and secure, but I assume you've already done that by now. Let me know if you don't follow any of that.

P.S. To locate the starter relay, take a look at the connections on the starter solenoid (the one mounted on the starter motor body). It will have three connections - two large and one small - follow the smaller wire back and it will lead you to the output terminal of the starter relay. Or alternatively, start at the battery positive terminal and follow the leads from there, one of which will connect to the input terminal of the starter relay.