Grand Marquis cruise control broken

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A year or so ago I had my '95 Grand Marquis cruise control fixed by a Ford dealer under a recall warranty thing to prevent fires from a malfunctioning brake sensor switch. You can read about it here: http://www.usautoinjurylaw.com/cases/fires/mercury-grand-marquis.htm

A few months later my cruise control stopped working. Has anyone else had this happen? Is there a fix I can do myself? It's been so long since the recall repair I doubt the dealer would fix it without wanting some $$, and they are such yahoos I really don't trust them. Thoughts?
 
You might want to at least call them...it is a recalled part. I would tell them I am afraid it is going to burn my house down.

OR find a Ford dealer who also sells Toyotas....they will be hyper sensitive to your request.
 
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Check out the basic's first. Maybe something simple. Check fuse's, wiring, bad connections, something came unhooked/unplugged, etc.
 
Unplug the cruise control connector from the brake master cylinder and check for continuity on that switch with a multimeter. Also check the fuses in the repair harness--if either of them are blown, do not replace them, but get a replacement cruise control deactivation switch. RockAuto has them for $10 or so, Motorcraft part. Then install the new switch (it just unscrews) and lose the repair harness with the blown fuses--the new switch comes with new repair harness which doesn't have any fuses in it, because the new switch doesn't need them.

Before doing all of this, check the fuse in the dashboard holder on the driver's side. I don't know which on it is on yours (it's probably the same) but on my '97 Crown Vic it's fuse 6, a 15-amp fuse. This fuse supplies power to the cruise control.
 
Which recall did they do? There was one to disconnect the connector at the Speed Control Deactivation Switch (SCDS) while there was a temporary parts shortage. Then when parts became available the dealer either replaces the SCDS if it was leaking, or installed a Universal Fused Jumper Harness if it was dry. there is a fuse in the jumper harness and the tag on it says that if the fuse blows to replace the jumper with the new SCDS. if this sensor is inop, it will not go into cruise control since it detects pressure on the brake pedal to discontinue use of cruise control.

for a random diag question, does your horn work? the controls for the cruise control go through the clockspring.
 
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Went through this with my 97 GM (and did the diagnostics-- but never got the green light on, so test failed at the get-go) but I think the clockspring was kablooey... lacking horn as well. At least the airbag light was off.
 
Everything bdcardinal said, plus:

http://www.p71interceptor.com/cruise/ (closest I could find online)

The servo pinout should be the same. You can check all of your voltages/grounds/steering wheel switch resistances at the servo connector. No idea on wire colors. As long as pinouts are the same, wire color is irrelevent.

If you need more info, I have a '94 Crown Vic/Grand Marq electrical manual around here somwhere, and can post copies of circuits/pinouts etc.
 
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hey punisher, totally unrelated but what do you think of the warranty extension on the Edge's with the cooling system flush? shortest its taken one of my very experienced line techs is 5 hours without cutting corners.
 
Thanks everyone! The horn does work, so I opened up the two fuse holders installed in the fused jumper harness. One of the 2-amp fuses is blown and one is OK. It sounds like I will try Brian1703's advice (above). Don't have my multimeter handy, so I'll check it tonight. When you unscrew the switch will brake fluid leak out?

"Unplug the cruise control connector from the brake master cylinder and check for continuity on that switch with a multimeter. Also check the fuses in the repair harness--if either of them are blown, do not replace them, but get a replacement cruise control deactivation switch. RockAuto has them for $10 or so, Motorcraft part. Then install the new switch (it just unscrews) and lose the repair harness with the blown fuses--the new switch comes with new repair harness which doesn't have any fuses in it, because the new switch doesn't need them."
 
A little bit of brake fluid will leak out, but not much. A few drips. This is according to what I read in the recall instructions.

If one of the fuses is blown don't even bother to test the brake switch, just replace it, with Motorcraft p/n: SW6351 ($10.93 at RockAuto).

That one of the fuses is blown indicates a failure of the brake switch. If the fuse hadn't blown, a fire could have resulted.
 
Thanks brian1703 for that part # too. On my car the switch is located on the bottom side of the master cylinder, making it a bit hard to get at. I'll replace it and see what happens. Do you think the new switch will not require the fused jumper wires?
 
The new switch will not require the fused jumper wires. The new switch has been redesigned to eliminate the problem with the old switch that required the fused jumper wires, which is that it would leak and short out.

The new switch has a different connector on it, so it will come with an adapter jumper cable to enable you to plug it into the existing harness connector.

You can discard the fused jumper wire, but I'd save it--it has the same connectors as a fuel injector and I could find a use for them!
 
Update. Replaced the cruise control brake switch from Rock Auto like brian1703 said and it works perfectly. While I was in there, replaced the plugs at 124K miles with Autolite Platinum. Old ones didn't look bad at all, except the gap was kind of large. Probably all in my mind, but it does seem like the engine is smoother and there is tiny bit more power with the new plugs.
 
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