Chrysler Repair: Cruise Control not working: LH body, postal mail, vacuum lines

Question
QUESTION: Hi My car is a 1999 Concorde and the other day the cruise would not engage.  I have power to the cruise light in the car but nothing happens when I press the set button.  I remover the servo and it is getting power fed to it from the on button in the car to one of the four connectors.  The diaphram in the servo is okay, and the control cable to the throttle body is working fine as well.  I checked the brake lights and they are working so I assume it's not the switch on the brake peddle that's stopping it.  Any ideas where I should be looking?  I'd like to fix this as I use it all the time.

Thanks Bill

ANSWER: Hi William,
The other things to check are the vacuum lines or for a leaking vacuum reservoir at the brake booster, and the vacuum check valve. Check to see if there is a fault code stored in the PCM; an Autozone parts store may do this for free, or an independent shop for around $40.
Check that the speedo appears to be working properly as that signal is needed by the cruise. There are 8 pages in the '98 manual that I have that shows the vacuum testing and general trouble shooting which I can xerox and postal mail to you. If you would then send me three 42 cent stamps after you get them that would cover my costs.
Use the "thank and rate" tab to get back to me where there is a comment section to enter your address.
Roland

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QUESTION: Hi Roland and thanks for the quick reply.  I own a OBD11 and checked and have No codes, the vacuum to the unit is so strong you could if you wanted to suck a golf ball through it.  I hooked up my GPS system and checked the speedo on the car against it and they were both the same.
I own the cars manual myself and have the same pages that you talk about or at least I'm assuming I have them.  It's the bought manual not the owners manual.

Bill

ANSWER: Hi Bill,
The most common failure point is the wire from the cruise control set switch where it passes through the clockspring at the steering wheel. So if you haven't tested that wire I would start there. Other than checking over the rest of circuit via the wiring diagram for it I don't have any other ideas.
Roland
Please let me know if you find the cause.

Hi Roland don't know if you got my last email telling you that I have no codes, I have removed the servo hot wired the #3 wire grounded the 2 & 4 wire and the servo didn't move which is correct I then hooked up the cars Vacuum line and grounded the #1 wire and the servo work as it should. So that proves the servo and the vacuum system on the car. What does that leave the speed sensor, the switches on the stearingwheel and the NO/NC switch on the break pedel, does it not? Any help here would be appreciated. Thanks Again Bill Bleasdale


Questioner:   William

Hi William,
I suspect the steering column clockspring wire is broken. The stop light switch would show itself by the brake light being "on" even though you weren't touching the pedal (see if it might be on a hair-spring alert, e.g. about to show if the pedal moved ever so slightly which could happen while you were in motion). The speed sensor would show itself by your speedo/transmission shifting being faulty.
My '99 manual shows that if you measure between the wires on pin 41 and 43 of the gray plug at the pcm you should show "open" until you activate any one of the 5 speed control choices at which point you should see a resistance reading. Try the on/off for sure. It is either the clockspring (if you get open no matter which position your try) or the switch itself if you get reading on every choice except the on/off. That would be my next step.
Roland

Where do I find the clockspring?


It is at the upper end of the steering column just in front of the steering wheel . There is about 11 steps to removing it and 11 steps to put it back. I would rather xerox copy and mail you these texts than to try to type them in. Once you have verified that the clockspring connection is no longer patent by electrical testing as I described, use the 'thank and rate' tab to tell me you postal mailing address.
Roland

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QUESTION: Hi Roland Have just checked wire 41 to 43 and it read open. I then tried each switch on the stearingwheel all of them closed the circuit.  So I think that circuit is okay.  I reconnected the cruise and stated the car and put the cruise on.  Using a test light I tested the #3 wire and got the 13.2 Volts and the Servo plug I then tested the #1 and #2 wires and got the same voltage but nothing on the #4wire.

To be honest I'm at a loss what to try next.  Do you have any more thoughts?

Answer
Hi William,
Have you checked fuses 1 and 20, just to be sure? The #4 wire at the servo is ground so that is why you saw nothing. Have you tried a fault code readout on the system? You can get that for free at most Autozone parts stores, and that might give you a tip as to what might be wrong. An independent shop would do that for about $40.
Finally, I can xerox and postal mail you the 10 pages from the shop manual so you can go thru all the tests and circuits. If you would send me three 42-cent stamps to cover my cost that would be appreciated. Let me know your address by means of the "thank/rate" tab below.
Roland