Expedition sometimes won't start

We have a 2012 Ford Expedition that at times won’t start. And it isn’t like it just doesn’t start…it is like there is absolutely no power what so ever. It doesn’t do it all the time but when it does and can be an hour or more of trying to start the truck. What is really weird…if you leave the key in the ignition in the “on” position sometimes the truck will just start up without even touching the key!! Of course every time we take it in it doesn’t do it. I has been at the Ford Dealer for a week and the truck starts every time they try it. We put a new starter (that was about $300), but the truck started doing it again. So it obviously wasn’t the starter. Now they are saying we can try putting in a new ignition (for about $700) but if that isn’t they problem either, we have spent $1000 on nothing! Help…surely some one else has had this issue and gotten it resolved.

First dumb question, do you have remote starter if so remove it.

If the non-start condition means you get no sound at all, then the problem is NOT the ignition. Perhaps they mean the ignition switch?

It could be the battery, or the battery connections or cables, or a relay, or the ignition switch.

I’d get a voltmeter and next time it doesn’t start, check a few points, such as battery voltage and starter voltage (at the solenoid and at the main starter terminal).

Also try wiggling the ignition switch next time I doesn’t start.

No remoter starter…and I did intend to type ignition switch. It isn’t a battery problem…that has all been checked out. I don’t remember anyone suggesting that it could be the solenoid at the main starter terminal. Thank you all for your suggestions. I appreciate it…keep them coming.

The problem might be with the Central Smart Junction Box.

This is a mini computer that controls all the electrical power that’s supplied to the vehicle.

The CSJB allows voltage thru the ignition switch to the starter relay which operates the starter.

The CSJB can also operate the starter relay even if the vehicle isn’t equipped with a remote start system.

Tester

You mean none of the accessories, i.e. lights, radio…, don’t work either in any of the key positions?

That’s right. It is sporadic, though. It will go days and weeks and start every time and then it will happen again. And as I said sometimes if you leave the key in the “on” position and just sit in the car it will all of a sudden start up without touching the key. But you can’t sit in the car in 100 degree weather hoping the car will start up.

That is probably where the problem is…but every time we take it to the shop the car starts every time. And they can’t figure out where problem is

Don’t sounds to me to be a problem with the distribution junction box. Seems more like an ignition switch issue. Just to clarify, normally interior or headlights do not need a key in the ignition to work. These lights do not work when the car does not want to start?

Unfortunately it’s often the case that intermittent problems like this can’t be easily diagnosed at the shop if they aren’t actually happening at the time the car is at the shop. If you’re willing to pay by the hour, I’m sure they’d be happy to spend as much time as you’re willing to pay for trying to solve it. But that might get pretty expensive, which is probably why they aren’t recommending that approach. One idea, instead of just leaving it with the shop where they attempt to start it up a couple times a day, ask them to allow one of their staff techs to use the car as their daily driver. Eventually the problem will show up and then they can either do the diagnosis on the spot or tow it to the shop right then.

I had an intermittent electrical problem like that on my old VW Rabbit years ago. I couldn’t get it to happen when I had my test equipment out and ready to probe. What I finally did was make a guess which wires were the likely culprits. Then I soldered extension wires onto each of them and ran these extensions to the passenger compartment. I brought along my volt meter whenever I drove the car. Then the next time it happened it was easy to probe the wires to discover some clues what the problem was. Ask your shop if it would make sense to do something like that for your case.

One more thing about a potential safety problem: If a vehicle starts on its own, that’s a potential problem b/c it could start a fire or fill a garage with deadly exhaust gas. I realize at the momement that happens only with the key in “on”, but still it is a good idea to park your expedition outside and away from buildings until the problem is resolved.

Intermittents are difficult. One I had was the car battery being dead when I tried to start the car, about once per year.

I had to guess at a solution, that the dome light was not going out every time… it worked on a timer and went off a minute or so after you closed the car.

I rarely drive at night, and this needed the car parked for 3-4 days to kill the battery, so it took me a while. Turned off the dome light and all was fine.