Mercury Grand Marquis auto won't shift into gear

My mother's 1996 Mercury Grand Marquis LS automatic won't shift into gear. She says that she has to pump the breaks dozens of times before it will shift out of park. Sometimes while pumping the breaks it will almost go to
the floor, then you can shift in gear. Someone thought it was pressure related and that breaks/shifting was interconnected. Break fluid was added and it made no difference. They tried messing with the linkage under the dash, but it didn't help much. Any ideas?
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[This followup was posted to alt.autos.ford and a copy was sent to the cited author.]
@hotmail.com says...

It probably has an electric shift interlock. When you step on the brake, it turns on a solenoid that unlocks the shifter. If the switch or solenoid go bad, you will not be able to shift out of park.
Also, make certain she is actually holding down the brake while shifting out of park.
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That sounds like a good possibility. Do you know where this solenoid might be located?

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Jobe wrote:

It's near the bottom of the steering column, if it's anything like the one on my Aerostar.
A common problem is the shifter linkage tube and the rod that slides inside it get bent or broken, as I found out from the Ford parts guy when I bought the parts for my Aerostar's broken shifter mechanism.
Coincidentally my shifter broke right after I had the van towed... I strongly suspect the tow truck driver didn't step on the pedal before trying to take the shift lever out of park.
Anyway, the solenoid itself may be the problem, or it could also be a problem with the switch on the brake pedal that controls the solenoid. Check the connectors to the switch and the solenoid to make sure they are pushed on all the way before doing anything more drastic.
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On Sat, 10 Apr 2004 20:41:10 GMT, "Jobe"

It is likely a bad brake light switch. If the brake lights do not work and the fuse and lamps are OK, it is more likely the problem.. You can check the lamps by turning on the 4 way flasher to see if they work. The bypass in a pinch is to turn the switch key out of lock and shift into nuetral where it will start. You can then put it into whatever position you want. You will have to do this every time you place it into park until it is repaired. BTW, Ford is recalling many late models for defective brake light switches and wires harnesses. I do not know exactly which models. I just got the one on our Sable.
Good Luck
Lugnut
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snipped-for-privacy@bellsouth.net says...

The recall is only for the 2000+ Taurus/Sable. This is the SECOND brake light switch recall for some models like my 2000 with adjustable pedals. In hot weather, grease on some springs and other parts melts and runs down the brake pedal and gets into the switch. That causes arcing on the contacts, which melts the plastic it is made out of. That causes the switch to get stuck on (happened to me TWICE) or off.
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Try this. Turn the key from "lock" to "off". The steering wheel will be unlocked, but there will be no instrument warning lights. Hold the brake pedal and move the shift lever to "N". Now start the car and shift into reverse or drive. This bypasses a malfunctioning shifter interlock.
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