I have a 96 F150 that I can't get out of park It also seems to have a leaking switch on the top of the master cylinder. I think this switch might have something to do with the problem. When the switch is connected the #13 fuse blows. Truck also has no brake lights. I haved voltage to both wires going to this switch. Is that normal, or is there a short in the wiring? I am hoping it is the switch, but I don't know why there is voltage to both wires. Help.

 

Not too sure about the electrical, but about the park thing: Is it in park on a hill? and if so then it may be because the entire transmission is resting on the park pin, therefore creating a TON of pressure, and all of it is resting on that pin. If not, then the pin may be worn down and the same thing could be happening.

 

Thanks for the tip, but no it's on level ground. I can put it in gear if I don't turn the key all the way on. I am pretty sure it's electrical, because I have seen other people ask kind of the same question. But so far I have not seen any answer posted. I think it's the switch but hate to just start replacing parts.

 

You do have some electrical issue, but I don't think it is causing the shifting out of Park issue, since shifting out of Park is a mechanical action. You mentioned that the position of the key switch effects your ability to move the lever out of Park. I'm not sure about your truck, but most auto trans vehicles have a key switch mechanism that prevents the shifter from being moved out of Park with the key in the lock position and from being shifted into Park with the key in the run position. That mechanism may be worn out and sloppy, causing you to have to fiddle with the key position to move the lever.

 

I checked my wiring diagram:

Fuse 13 services the brake light switch and hazard flasher.

The brake fluid warning switch is serviced by fuse 17, as is the oil pressure switch and gauge/light.

On the brake fluid warning switch, the tan/light green wire goes to the ignition switch. The purple/white wire goes to a 'brake warning resistor/diode assembly', then continues on to the instrument panel brake warning light. There is a light green/red wire that comes off that 'diode assembly' and goes to the parking brake switch. There is also a red/yellow wire comming from the fuse box (fuse 17).

It appears that it is normal for both wires going to the brake fluid switch to have power when the key is on and for only the purple/white wire to have power when the key is off. The switch appears to work by grounding the purple/white wire which activates the resistor/diode thing and sends power to the warning light on the dash. The parking brake switch appears to work the same way.

It doesn't appear to me from the diagram that there is a connection between the #13 fuse circuit (brake light switch, hazard flasher) and the #17 fuse circuit (brake fluid warning switch, parking brake switch, dash warning light). I don't see a logical explanation for connecting or disconnecting the brake fluid warning switch to have an effect on the brake lights, unless there is more to the wiring than I'm seeing on this diagram...

I'm not all that great with auto electric but that's my take on how it works from looking at the diagram. Hope that helps some...

ON EDIT:

Does your truck have cruise control? There is a 'brake pres switch' on fuse circuit #13 (same curcuit as the brake light switch). I'm not sure where this switch is but maybe this is the leaking switch? If so, this might explain the connection between the leaking switch and the brake lights...

 

I found out the switch on the master cylinder is actually the cruise control deactivation switch. Thanks for the wiring information. Apparently the deactication switch has something to do with fuse 13, which keeps on blowing. I am now just umsure whether I should have voltage to both wires.
One wire is green and the other is maybe black/green. Ford get's about 25.00 for this switch, so I would rather be sure.

 

I'm not finding any switch listed in the diagrams called a 'cruise control deactivation switch', but I do find that the 'brake pres switch' I mentioned earlier does connect to the 'cruise control servo/amplifier assembly' on one side with a white/pink wire and the second wire (red/white) ends up going to Fuse 13 after going through a connector that hooks up to the light green/red wire from the brake light switch, as well as going to the hazard flasher.

That brake light switch (on the brake pedal arm) has 2 wires of colors light green/red (from fuse 13 as mentioned) and light green, which goes to a few places (RABS module pin # 11, trailer brake controller plug, PCM pin # 2) and it also goes to the cruise control servo/amp but only on 5.8L Lightening models. Is your truck a Lightening?

 

Problem solved! The switch on the top front of the master cylinder was bad. It does deactivate the cruise control.It also is in the circuit for the brake lights. When it leaks fluid gets in and shorts out the wiring, blowing the fuse to the brake lights. Once this was replaced, the system worked fine. Thanks for the help.

 

Glad you got it fixed! What was the name of that switch, by the way?

 

I believe the dealer called it a cruise control deactivation switch or cruise control switch. The part number was SW5945 if you have access to it by part number. When they go the terminals appear all wet with brake fluid, and it fries the internals of the switch. Thanks again.