Cruise Control Woes

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BallerLincoln

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Before I begin, Yes I have replaced the clock spring. Again, it has been replaced.

The cruise light will flash on when I press the "set" buttons then go away within 1 second. A couple of times it has bumped my RPMs like it was trying to catch it, but it shuts off before it can do anything.

I have replaced:
Clock spring
Steering wheel buttons
Speed control module (twice)

Things I have checked:
Brake switch seems to be working (turns brake lights on and off).
Cable is attached to throttle body, and is not broken.


I cannot find any fuses/relays that pertain to cruise control/speed control.
Could this be a speed sensor problem? Where do I look for testing these?
Where do I go from here?
 
It's impossible to help without basic info on your car, such and year and engine. Very different cruise control systems were used on different years.
 
Wow, I can't believe I left that part out.

It is a 2001 with the 3.9, nothing special done to it. It's all stock minus a few cosmetic things. 176,000 miles. Runs great, and everything(minus cruise) works just as it should.
 
Most likely then, you need to replace the mechanical cable assembly between the cruise control servo and the throttle body. Sometimes the plastic at the ends breaks.
 
joegr said:
Most likely then, you need to replace the mechanical cable assembly between the cruise control servo and the throttle body. Sometimes the plastic at the ends breaks.
Click to expand...

When I pulled the cable off the speed control servo I pulled the cable and had a buddy watch the throttle body. It does open the throttle when pulled. Wouldn't this confirm the cable is functioning properly?
 
I've been thinking about this, and I'm thinking it has to be a speed sensor of sorts. But it isnt throwing any ABS or AdvanceTrac codes/lights.(or any for that matter)

Is there a way to test these without an Oscilloscope?
 
BallerLincoln said:
I've been thinking about this, and I'm thinking it has to be a speed sensor of sorts. But it isnt throwing any ABS or AdvanceTrac codes/lights.(or any for that matter)

Is there a way to test these without an Oscilloscope?
Click to expand...

The best way is with an oscilloscope. As long as your speedometer is working, a wheel speed sensor isn't your problem. If you're certain it's not a servo cable, then you need to scan it with scan tool that can read the Ford specific codes and sensors to find out what is happening.
 
So I read my codes, it's showing p1567 and p1568. Those are "Speed Control Output Circuit" and "Speed Control Unable To Hold Speed".

This definitely confirms my beliefs of a speed sensor of sorts. DTCSearch.com shows the codes have the same cause of " Engine running and the PCM detected a fault in the VSS input".

This seems more like the transmission output sensor that a wheel sensor, correct?
 
P1567 - Output circuit. This could be a few things, but since you've changed the module complete with the servo (correct?), it is narrowed down a good bit. This is especially true since I think yours is one of the years for the recall on the cruise safety switch.

On your brake master cylinder is a switch that power for the cruise servo passes through. The reason for this switch is that even if everything else fails, when you press the brakes and build hydraulic pressure, this switch will kill power to the cruise control servo - making sure that the cruise releases the throttle. The recall was to add a fuse in between the switch and the factory harness. (You may recall that Ford had big troubles with unattended car fires for a while there.) Check the fuse, wiring, and switch. There should be 12V all the way through.

P1568 is simply the result of the problem above. It's a code that says "Hey! The cruise control isn't working."

I don't see anything with either code that implies any sort of speed sensor issue. I also don't see any of the codes that do indicate speed sensor issues.
 
joegr said:
P1567 - Output circuit. This could be a few things, but since you've changed the module complete with the servo (correct?), it is narrowed down a good bit. This is especially true since I think yours is one of the years for the recall on the cruise safety switch.

On your brake master cylinder is a switch that power for the cruise servo passes through. The reason for this switch is that even if everything else fails, when you press the brakes and build hydraulic pressure, this switch will kill power to the cruise control servo - making sure that the cruise releases the throttle. The recall was to add a fuse in between the switch and the factory harness. (You may recall that Ford had big troubles with unattended car fires for a while there.) Check the fuse, wiring, and switch. There should be 12V all the way through.

P1568 is simply the result of the problem above. It's a code that says "Hey! The cruise control isn't working."

I don't see anything with either code that implies any sort of speed sensor issue. I also don't see any of the codes that do indicate speed sensor issues.
Click to expand...


Awesome, except I don't see anything on the master cylinder except the low fluid level, and the two plugs that read the front and rear pressure. I've found that unplugging those makes my advance trac light come on.

I see no fuse or switch. What am I supposed to be seeing/where should I be seeing them?
 
BallerLincoln said:
Awesome, except I don't see anything on the master cylinder except the low fluid level, and the two plugs that read the front and rear pressure. I've found that unplugging those makes my advance trac light come on.

I see no fuse or switch. What am I supposed to be seeing/where should I be seeing them?
Click to expand...

It would be out on the top at the front. Maybe I am wrong about that year. If it's not there, then there will be a mechanical switch under the dash connected to the brake pedal. This will be separate from the brake light switch.

...

Just checked the 2001 wiring diagrams. It is shown as a mechanical switch on the brake pedal support. Sorry about that. It will have two orange/yellow wires attached to it. It is sourced by fuse 235, a 5A fuse in the interior fuse box. This circuit should be hot even with the key off. It runs out to the cruise module, pin 6, and to the PCM. It's still orange/yellow at the cruise module. It's orange/green at the PCM, pin 28. I had this type of switch fail on a 99 Grand Marquis once.
 
I pulled the switch and checked it with an ohms meter, it tests fine. I looked at the fuse, tested the circuit with a multi meter, everything checks fine. I'm assuming the PCM is located just above the fuse box? I will have to pull it down from the dash to see the wires?

It's a little rainy tonight to check the wire on the speed control module, should it be hot at all times too?
 
Were the clockspring and switches new or used/junkyard units?
 
The clock spring was new, buttons from the junkyard. But I always grab doubles, and Im just going to assume that I dont have three bad sets of buttons. I will check the wire at the speed control module this afternoon. Would it hurt it to run a hot wire "jumper" if that wire isnt hot? Just to check it and see if will fix it?

Thanks for all of the help guys, I really do appreciate it.
 
No, but I wouldn't leave it that way.

About the cruise control modules themselves, were those used/junkyard parts?
 
OK, silly question. Are you sure all the connections are secure? Are the connectors brittle, cracked, or in any other way less than "ideal"?
 
BallerLincoln said:
First one was junk yard, second was new. Both yielded the same results as my original one.
Click to expand...

Hi BallerLincoln , just wondering if you solved your cruise control issues or not . I have the exact same problems with my 02 ls ....Dave
 
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