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Discussion Starter #1
I have a 1991 5.0 LX with auto trans and my cruise control doesnt work, I dont think I have ever seen a fox body mustang with a working cruise control system. What goes wrong with them? How do I fix mine?
 

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mine works but it does a weird pulsating thing. it gives too much gas, then coasts,gives too much gas, then coasts etc. it's worse in 3rd or 4th than 5th gear.
 

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There is a vacuum controlled mastercylinder up behind
in the driverside wheel well kinda behind the door hinge
that has an internal diaphram that goes bad after a while.

Usually needs to be replaced. Part isnt that expensive, but
it sure is a pain to get to.
 

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Most likely a failed servo module. Run through this check list. Check out the included link.

Parts/components you need to check:

1) Horns works - clock spring probably okay.
2) Brake light not stuck on.
3) If manual tranny, check clutch safety switch.
4) Pull codes, check for any related to the VSS sensor.
5) Also, there is a vacuum dump valve on the brake pedal assembly. Pull the dump valve and plug the line. Check cruise function.

If all of those check out, the servo module has most likely failed.

Check this link for more info.

http://forums.stangnet.com/768831-cr...ntrol-one.html
 

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Discussion Starter #5
When I push the "on" button on the steering wheel the light doesnt come on, on the gauge cluster. What would cause that? At least I have a place to start now.
 

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My light doesn't come on either, but the cruise still works. Have 100k on it. Didn't even know they put cruise in 5-speeds Foxes until I found this car.
 

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What light are you talking about? Fox bodies don't have lights that illuminate indicating that the cruise control system is turned on........................
 

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mine works but it does a weird pulsating thing. it gives too much gas, then coasts,gives too much gas, then coasts etc. it's worse in 3rd or 4th than 5th gear.
That's an easy fix. There's too much slack in the cruise controller cable. Pop the throttle cable assembly off the bottom of the throttle body. You'll be able to remove a small clip in the cruise controller part of the cable assembly, take out the slack, and reinstall the clip. Pop the assembly back on the TB and you're done.
 

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Cruise control servo

I have one in my garage if you determine yours is bad. I would ship it to you for the cost of shipping and a 12 pack of beer. Let me know.

Al...
 
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That's an easy fix. There's too much slack in the cruise controller cable. Pop the throttle cable assembly off the bottom of the throttle body. You'll be able to remove a small clip in the cruise controller part of the cable assembly, take out the slack, and reinstall the clip. Pop the assembly back on the TB and you're done.
thanks. how does it pop off the tb? I looked at it but wasn't ready to start yanking on it. it looks like maybe you just pull it straight down?
 

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Just pry it straight down. It's got a socket that snaps onto a ball on the bottom of the TB arm.
 

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Most of my Fox cruise failures were due to the cruise cable breaking at the servo linkage... Unfortunately, this part is no longer available new from Ford, so a junkyard will have to suffice.

I have gone through three cruise cables in 290k miles.

http://forums.corral.net/forums/showthread.php?t=1082434
 

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Discussion Starter #14
Okay this was probably answered but how do you know if the system is coming on?
 

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Okay this was probably answered but how do you know if the system is coming on?
If the cruise is broken, you won't know, since there is no visual indicator. If it is not broken, it will be obvious when it turns on. Good old fashioned troubleshooting skills are very handy when dealing with a Fox body cruise control.
 

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Discussion Starter #16
Okay so it turns out you have to have a fuse installed in the fuse box for the cruise control to work. Consequently the same goes for the horn.
 

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Mine is a 1993 and it has a cruise control light letting u know it on.

thank the good lord........

how would you have ever known it was ON?????
 

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Mine is a 1993 and it has a cruise control light letting u know it on.
It does?

Do you have a pic because i don't ever recall seeing a cruise light in the cluster on a 1993 before.
 
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There is a vacuum controlled mastercylinder up behind
in the driverside wheel well kinda behind the door hinge
that has an internal diaphram that goes bad after a while.

Usually needs to be replaced. Part isnt that expensive, but
it sure is a pain to get to.
Most of my Fox cruise failures were due to the cruise cable breaking at the servo linkage... Unfortunately, this part is no longer available new from Ford, so a junkyard will have to suffice.

I have gone through three cruise cables in 290k miles...
Probably where mine is broken, but getting to the servo is too much trouble for something I don't use any more.
 
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