Augster

Shorted the brake light wiring by accident when swapping out third brake light and now none of the brake lights work and the transmission brake-shift interlock engages.

I've checked the two fuses (#6 20A in passenger fuse box and #46 15A in power distribution box) and both are good. Reinstalled the factory third brake light and still no-go. Third brake light bulb is good as I tested it in the cargo light sockets.

I pulled the tail's and all 4 bulb filaments look good. I have 4 new bulbs but I'm now doubting the bulbs are bad since the filaments are intact.

I'm beginning to think the stop light switch is shorted but before I go replacing it, does anyone have any suggestions of what other component to check? I can't imagine anything else beyond the 5 bulbs, two fuses and brake switch.

In the meantime, I have to use a screw driver to disengage the interlock every time I want to shift out of park.

<rant on>
Which brings me up to a point of contention: the manual is not really accurate in describing what tool you need to remove the little access cover over the interlock disengage button on the transmission bezel. It states to use a screwdriver, but the little cutout to get a tool in there is way too small for ordinary screwdrivers, and only a jewelers flat tip or the point of a thin knife is all that can get in there.

Besides, the interlock is said to engage whenever a brake light bulb goes out or there are any other problems with the stop light system. If you don't happen to have a little jeweler's screwdriver or thin blade handy, you're going to tear up your transmission bezel getting that frickin' small access cover off in order to disengage that brake-interlock and be able to drive your vehicle to get it repaired. Crummy design and instructions.

I will now be packing said tool in the truck just in case this happens again out in the sticks.
<rant off>

EDIT: It ended up being the 15A fuse after all, even though upon magnified visual examination it appeared to be fully intact and there was no detectable point along the fuse having burned out. I got a fuse variety pack with tester and used it to check both fuses and found the bad one. Goes to show you that Ford's fuses may no longer display any outward appearances of having burned out and using a tester is the only way to be certain.

ilmo

Where is this transmission bezel you are talking about exactly?
I guess I missed this in the manual.

ji603

I think he must have the console shifter, and be referring to a little access hole cover. It was like that on my toyota, but now I have a column shifter in the f150, and that bypassing the brake interlock is a pain in the ***. You actually have to pull that rubber boot off the column and dick with a lever inside the steering column.

Oh well - idiot lights, buzzers, bells, seat belt minders, airbag switches - can't buy a normal truck anywhere these days.

ilmo

OK. Just read the manual on this. Didn't even know something like this needed to be done if you had a blown fuse or brake light failure. My last truck was a 2000 F150, so nothing like this procedure had to be done. At least, I don't think so.

Starts on page 289

BRAKE-SHIFT INTERLOCK - COLUMN-SHIFT TRANSMISSION
This vehicle is equipped with a park/brake-shift interlock feature that
prevents the gearshift lever from being moved from P (Park) when the
ignition is in the on position unless the brake pedal is pressed.
If you cannot move the gearshift lever out of P (Park) with ignition in
the on position and the brake pedal pressed, it is possible that a fuse has
blown or the vehicle’s brake lamps are not operating properly. Refer to
Fuses and relays in the Roadside Emergencies chapter.
If the fuse is not blown, perform the following procedure:
Note: The following procedure is easier to perform when the steering
column is adjusted to the full up position. Refer to Tilt steering wheel in
the Driver Controls chapter.
1. Apply the parking brake, turn the ignition to the off position, then
remove the key.
2. Move the shift lever boot by
pressing on the edges and moving it
up the gearshift lever.
3. Turn the steering wheel one-half
turn to access the slots on each side
of the steering wheel.
(I don't really know how you would step 3
if the steering wheel is locked with the ignition
in the off position and the key removed).
4. Insert a flat head screwdriver into
each slot to unsnap and remove the
steering column cover. Rotate the
column up on its hinges and pull
rearward to remove the cover from
the hinges.

Augster

Column shift versus floor shift have different procedures. I have the floor shift, and hence my frustration at the way of getting to the brake-shift interlock (although, it sounds like an awful lot of steps and potential conflict to get a column shift transmission out of park). An ordinary flat-tip screwdriver would be easy to come by, if not already in your emergency kit on board. But a jeweler's screwdriver or thin bladed knife?

Regardless, the fact that the transmission will automatically prevent you from shifting out of park if the brake light system blows a fuse and/or has burned out light bulbs is unbelievable. Yes, I understand the dangers of driving without stop lights, but why couldn't the designers provide very clear warnings instead of a complete lockout that prevents you from using the transmission without the proper tools at your disposal (and reading TFM).

I'll provide pictures tomorrow when there's light since I still have the square "plug" out. Hopefully this will help others better understand what to do in the event they experience the brake-shift interlock preventing them from shifting out of park normally. For 4WD trucks, this is especially crucial since you are not supposed to have it towed on any of its wheels, and with the rears locked up, it will take some work to get it winched onto a flatbed. Unless you don't mind gouging up your console cover a bit in order to get that plug out if you don't have the right tools available (or disconnecting both driveshafts).

ilmo

I agree with this 100%. I would not have known of this type of problem if you hadn't posted about this and undoubtedly would not have known what to do other than call for help.

Bob_Mac

Ouch, guess it's time to stock some extra bulbs and leave in truck just in case. Would hate to get stuck somewhere and have to go through this procedure.....

Augster

If I wasn't working on the brake lights, I may not have figured out why the transmission was locking me out of shifting out of park.

Here are the pics. The brake-shift interlock cap is located in the upper right corner of the transmission shift bezel. I actually was wondering what that little "square" was for the other day. Now I know.

I used an electronics screwdriver with a 3/32" flat tip, but an equivalent sized jeweler's screwdriver would work just the same. As you can see, this type of screwdriver is all that could possibly fit into that tiny slit used to pry out the plug. Anything larger would result in nicking/gouging the bezel.

ilmo

I just checked the wife"s 2009 Flex and it has the same thing.

If this problem would have come up on one of my vehicles and could not get it out of PARK, I would have said something happened to the transmission. I would have never suspected that a fuse or brake light bulb to be the culprit. This is just.....amazing. Why not some type of warning light or something other than this?

I am sure that I was the only one that did not know this.

I will also be making a trip for some spare bulbs, too.

Thanks.