I am posting this just in case it helps someone with the same mysterious problem. First I wasn't able to move the shift lever because the shift interlock was in the on position all the time. Second, the automatic door locks stop working and finally (I discovered this later) the brake lights didn't work.

After checking the troubleshooting section and other chapters of the manual, by elimination I found this could be caused by a faulty brake switch. Many other conditions may cause this, but this was my case. I changed it, but no changes in the system. The old switch was good.

It wasn't until a conversation with a friend (he is a mechanic that went through three of this cases) that I finally learn the problem cause was a broken wire at the brake switch female connector. They tend to brake because of fatigue (pedal moving back and forth). I fixed the connection and OKEEDOKEE. Everything working again.

This switch is related to many functions including the three mentioned in the first paragraph. It lights the brakes lights, controls the locks and disactivates the shift interlock.

 

That's good to know! Thanks for the post.

 

and disactivates the shift interlock


thats a good point...dont ever try to put it in gear without the brake pedal pushed down..you could pull the tranny cable out of the "holder" in the tranny...happened to me in a snowstorm...right when i needed to go plowing...i re-attached the cable...but on your back in a snowbank was no fun at all...so dont do that! :o ...zap!

 

There is a way out of this since I kept using the truck for many months with the condition. Before starting and turning the key just pull back the lever and then start the engine. Don't let go the lever to the forward position in park but move it to another gear, usually I moved it to neutral to warm up the engine. From there you can move the lever to any gear unless you go back all the way to the park position where you will have to start all the process again since the lever will get locked.

If this happens to someone this would be a good choice to get back home without breaking anything.

 

It also sends a signal to the speed control servo to kick off the cruise control when you tap the brake pedal. Your situation (i.e. a bad switch or wire) is exactly the reason they incorporated the (now defective) pressure switch on the master cylinder.

As for the pin causing the linkage to pull off the trans.... no way Jose. The brake-shift interlock pin is located in the steering column, not on the trans. It locks the lever, preventing you from pushing or pulling the cable. The fact that it fell off where it did was mere coincidence.

-Joe

 

That's right. I mentioned all this not because of your case but for information only to protect someone that may be tempted to force the lever too much.

 

For RCS3 or anyone with the same problem.

If you identified that the problem is one or both wires at the female connector you can do this.

Disconnect the female connector and remove some of the tape at the wire loom so you can get more lenght of wire. Strip it and then go to the connector.

Remove the metal connector (if you can not get a new one) from inside the plastic housing (female connector) and try to open it with a very thin screwdriver or similar to remove the remains of the split wire. This part was very tedious. Once completed you can crimp or weld to this connector the corresponding wire. I did not have my soldering gun at the time. Then you insert back the connector into the housing (reverse of removal) and connect this assembly (female connector) to the brake switch for a test. You should be fine.

I like to work in my truck and I prefer to solve problems like this by myself.

I hope this helps. Let me know if you need more info.

 

JMTruck,
I wanted to let you know I had to replace the entire switch. I was able to take the panel off the rear of the switch and look at it using a mirror . I discovered that the copper plates were burned out. So a trip to the Ford dealership parts center and $15.00 later: and a lot struggling to get into the right position to get to the brake switch! the brake lights are working! I tried getting the part from Auto Zone but apparently they must be using a new brake switch because the part was completely wrong.

The nice thing about this situation was the ability to actually do the repair myself with a little help!

Thanks again!

 

It's rewarding to be able to acomplish tasks like this one. I love to work on my truck.

I am happy for you. See you later.