Hello All:
Recently my cruise control and shift lever have been giving me trouble. When cruise control is engaged, pressing the brake doesn't stop the cruise control. I can feel the brakes being applied but the cruise control continues. Also, after starting the engine, pressing the brake doesn't allow me to take the shift out of Park. Searching on the forum, I saw similar problems related to the BPP switch going bad.

Does anyone have instructions on replacing the BPP switch on a 97 EB Expedition ? Is it easier to access by removing the dashboard knee bolster and dash trim ?

Thanks for any and all advice

 

First I'd check fuse 13. It is a 15A fuse that feeds power to the BOO (Brake On Off) Switch and to the BP (Brake Pressure) Switch.

When the brakes are applied, the BOO switch feeds 12v to the speed control servo so it knows to disengage the speed contol. The BP Switch is there just in case the BOO Switch should fail, in which case if you lean hard enough on the brake pedal, the BP Switch will supply the signal to the speed control module to disengage the speed control.

The BOO Switch also supplies current to the Shift Lock Actuator so that when the brake pedal is applied you can shift out of park.

So if you can develope enough brake pedal effort so that the speed control will release, then your issue is with the BOO Switch. But if heavy brake pedal effort will not cause the BP Switch to release the speed control, the problem is more than likely that the fuse feeding the BOO and BP switch is the issue.

Has this vehicle had the Speed Control updated by way of the Ford recall?

 

Thanks for all the info. I'll check the fuse. I presume this is the fuse under the dash ? BTW, where is the BOO switch located ? Is this the one attached to the brake pedal ? I've been referring to it as the BPP (Brake Pedal Position) switch based on comments on other threads.

Yes, it has.

 

You need to first see if the brake lights work. If they don't then this is the correct course of action.

BOO=BPP

The relevant F13 is in the under-hood fuse box.

There have been reports of the wiring that goes to the BOO switch also causing this problem. Usually it has been due to the wire breaking off inside the insulation within several inches of the switch's connector.

Even though you had recall 05S28 performed, check the SCDS on the master cylinder for the presence of fluid in the connector. Some of the recall harnesses had problems that might result int he fuse not blowing when it should have.

 

Thanks for the response, projectSHO89. Actually, it's not only the cruise control that is giving me trouble. I also have trouble shifting out of Park, so, I'm not sure if it's related to the switch connected to the brake fluid reservoir under the hood. Also, this problem is intermittent so on some days (like today) everything works fine and the brake lights are working. I'll have to check the brake lights when I have trouble shifting out of Park to be sure, though. Fuse 13 under the hood is related to the aux. blower according to page 137 of the user's manual. Fuse 13 under the dash is fine and is the one for the BOO/BPP according to page 141.

As for the BOO wiring, is there an easy way to test if the wiring is okay. Like for instance, checking continuity or connecting 2 of them to see if brake lights go on, etc. I have a Multimeter so I can check for these things.

Cheers

 

You're right, it is the fusebox under the dash. I looked at the diagram and misinterpreted it.

The brake lights, the shift lock, and the speed control all depend on the power supplied by fuse F13 for proper operation. That's why it's important.

Yes, do that. It will tell you if you have a problem with the power to and through the BOO switch.

Easiest way to check the wiring to the switch is to have someone watch the brake lights while you simultaneously push the bake pedal with one hand and wiggle the wiring harness with the other. It's it's intermittent, your partner should be able to tell you. The good news is that if it fails all the way, it becomes a lot easier to diagnose with a meter.

 

Well, I squeezed myself under the dash this morning and when I touched the BOO/BPP the wire that comes off the bottom of the switch simply separated from the electrical connector. I didn't tug on it or anything so it looks like it must've been failing for a while and hanging on by a few strands. So, next question is, how do I get the electrical connector off the BOO. I tried tugging on it but it stayed put and I didn't see any plastic tabs that were holding it in place. At the very least, I need to reconnect this wire and possibly check the other wire that goes into the connector as well. I'd rather not take the entire switch off the pedal simply to fix the connector.

Thanks for any help