Another shift interlock issue

[jman]

2008, 170K. Brake pedal/light switch is good, solenoid on shifter moves when 12v jumped to circuit so it is good. Not getting any power to solenoid wire when brake pedal is pushed. Fuse 5 is good. I am obviously missing something between the break switch and the shifter solenoid.
When I started to have problem it was gradual, sometimes just had to push brake pedal down twice and it would go but eventually stopped working. Need to get the Expy ready for my daughter to drive so cant really expect her to have to mess with the emergency release every time she gets in. Any help is appreciated.

 

[07navi]

J Expy and I both had those problems and we both didn't realize the brake light wasn't always working. I think the juice goes through the the tail light switch before it gets to the solenoid on the shifter that unlocks the park lock. I would start by putting a new brake light switch in. That might be all it is plus it needs to be positioned correctly for the brake pedal/arm to operate it well.

 

[jman]

Has a new switch and brake lights seem to work fine, multiple applications at different times and lights come and go with pedal application as they should.

 

[07navi]

Has a new switch and brake lights seem to work fine, multiple applications at different times and lights come and go with pedal application as they should.

Hmmm I guess you will have to look for a short in the wire going to the solenoid or maybe the new switch malfunctions or it isn't adjusted correctly for a good push from the brake arm. I still think it is switch related because it was working sometimes and then quit which doesn't sound like a short. I would test for juice getting to the solenoid again also.

 

[jman]

Brake switch adjustment would only be a factor if the brake lights did not turn off when the pedal came back up, the switch operates in a "plunger out" configuration and only has about 1/4" of travel before contact is made inside the switch, it takes very little movement, idea is that the brake lights react quickly to any brake input.

Does anyone have a factory schematic for the wiring of the interlock??

 

[07navi]

Strange how it wasn't "all or nothing" but it worked sometimes and it required 2 pumps sometimes. That means it's not a fuse and if no power gets to the solenoid anymore that leaves the switch but you said it was new so maybe it is defective. Obviously an open circuit somewhere and not a short. Keep us posted.

 

[Trainmaster]

It's all right there. Can you remove the switch or work it with your finger while listening to the solenoid? Some switches are "permanently self setting" the first time you operate them. If you don't get it right on the first installation, the switch's messed up and you throw it out. I learned that the hard way. Don't know if the Expedition's like that but the Crown Vics were.

I'm with 07Navi on this. I'd say the problem is the switch because of its intermittent nature. You mess with the switch and it works? Gotta be. If not that it's a ground or a wire.