I have a 2008 Expedition EL Limited, auto trans, auto 4X4, 5.4L. I started it twice last Sunday for some really short trips (to and from the neighbor's house). When I went to move it in the driveway in the evening, it wouldn't start.

Starter does not engage, that is it does not turn nor seem to try to turn.

There is a low volume click of a relay near the passenger footwell fuse box (I think this is the relay that disables all other accessories during a normal key-turn to start condition).

There is no clicking sound under the hood nor under the vehicle upon turning the key to start.

Battery has 12.75 volts. When the key is turned to start, it drops to 12 volts. I tried hooking up a charger but no change.

Fuses under the hood are all ok.

Positive wire at the starter is getting 12.75 volts as a constant source.

My general Haynes manual and all I can find online seem to reference a separate starter relay on the firewall or inner fender like all older Fords I've owned but I don't see one. Is there a separate starter relay/solenoid on this vehicle, if so, where?

I did test the starter solenoid mounted to the starter. It has no voltage when the key is not pushed to the start position. When I have an assistant turn the key to start, that post gets 12+ volts.

Does this mean the starter is faulty? Or do I need to test anything else. Do I need to try further to test the transmission range (position) sensor ir the ignition switch?

I don't mind swapping out a starter but I'd hate to find out that is not the issue. I'd hate to pay to have it towed to a shop for something I can do in my driveway.

 

See if you get voltage out of the solenoid when your assistant turns the key. I haven't had to touch the starter in my 08 but there may be a strap or wire between the solenoid and the starter. If you get no voltage out, the solenoid is NG. If you get voltage to the starter it is probably the culprit.


Good luck...sorry I am not more familiar with the starter on our Expys. (Actually, I'm not. I hope I never find out).

 

I did one more test over the past weekend. I had my assistant (daughter) turn the key to start in various shifter positions (P, R, N and D). The starter positive pole still has 12 volts constantly regardless of key position. The solenoid pole on the starter does get 12 volts when the key is turned to start when the shifter is in P and N but not in D and R.

That means to me that the transmission range sensor is working properly. Now I just need to get the new starter and swap it out with the old one.

 

Final update:

I replaced the starter on the 08 Expedition over the weekend. It is a tight space to get the old one out and the new one in but doable on jack stands.

The top (of 3) starter bolts is a pain to get to. Standard 6 inch (?) 3/8 inch ratchet extension is ok to use to get that top bolt to start to loosen it but then needed to switch to a combination of two shorter extensions that was less than the length of the single extension. The single extension ratchet combination backed into other parts and I actually had to turn that bolt back in to get the ratchet off the bolt head then switch to the slightly shorter combination.

A flex join for the 3/8th drive ratchet comes in handy too for the other two bolts.

I reconnected the electrical connections (set off the security alarm when I reconnected the battery at 8:30 PM in the driveway - neighbors love me!) and she started right up when I turned the key!