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Discussion Starter #1
Crusie control light comes on when swtiched to on on the instrument panel but cruise control not setting.

I noticed a green connector close to the relay compartment under the hood that is not connected to anything. Figured that was to disable the seat belt warning bell since it does not function.

Any ideas on this cruise control problem?

Thank you.
 

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1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
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I'm Going To Assume That You Are Mechanically Inclined. I Will Also Assume You Have Inspected The Servo For Hoses Fallen Off And Electrical Connection Secure. Also That The Rod Going To The Throttle Is Intact And Pulling On The Throttle Lever If You Slightly Collapse The Servo. If All That Is Ok, I Would Drive The Car Above 35 Mph. Put My Foot Under The Brake Pedal, Lifting Up Slightly. Set The Cruise Button . If It Now Works, Adjust The Brake Light Switch. Adjustment Is Done By Pulling Up On The Brake Pedal Hard To Force The Switch Up In The Retaining Bracket. Also In Some Cases If A Hard Code Is Set In The On Board Diagnostics , The Bcm Or Ecm Will Disable The Cruise Control Until The Problem Is Corrected. Check For Any Current Hard Codes And Fix The Cause. You Will Need A Cadillac Service Manual, Not A Haynes, Not A Chiltons , To Properly Diagnose Any Codes. I Hope Its Something Simple. Please Keep Us Posted As To Your Final Repair. Good Luck, Bill.
 

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Discussion Starter #3
Thanks for the advice. Seems like this could be a simple fix.
Gonna look at it tomorrow. Why the auto manufacturers don't provide a detailed service manual with every new car sold is quite unreasonable, imo, especially after almot a century of automobile manufacturing. I know lots of people think they are greedy and purposefully trying to keep secrets from the general public just to garner more money in repair bills. Seriously. Consider how much a new vehicle costs now, and how much a service manual would be?
I would be very happy to get a ful service manual for a new car for $100 extra.

Would you?

The automobiles are designed, engineered, manufactured and there are already detailed planes on every part on these vehicles.

Now, in the internet/information age, maybe we will get what we need to maintain our cars soon.
 

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Discussion Starter #4
Found two hoses disconnected upon inspection but this did not fix the cruise control. The hose to the servo was not on, so I thought that woud fix it.
Hose was cracked, too.
Is there a vacuum pump which sucks on the servo?
Everything LOOKS good at this point but it has not started the adctual cruie function uyet.
I get Cruise engaged light, but ti does nothing to maintain speed and the resume accel does not work either.
I guess there is just no suck going on.

I cleared all the codes in the DIC.
I was getting B120 B121 and B552(memory reset) history codes. Twilight sentinel stuff and bcm memory reset (I guess).
Now no codes are setting at all and it sayus everything is ok.

Thanks for the help. maybe I will get a new hose to connect to the servo from the vacuum tube. Do you know where that tube goes? Seems like it coulda been going back into the car.
 

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1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
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the hose going into the car attaches to the dump switch on the brake pedal bracket. if off, cruise wont set. also if the switch is misadjusted it wont send current to the transducer. push the switch deeper into the bracket, then pull up on the brake pedal. that should adjust the switch. the engine vacuum source hose to the transducer should have vacuum at all times. thats what is metered thru the transducer to the servo to control the amount of vacuum is used to retract the diaphram. good luck.
 

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Discussion Starter #6
FIXED IT!!!!!!!

Checked everything.

Then removed the servo, looked at the hose connections and there was a piece of hose lodged above the connections which was preventing a good seal. The larger hose had ripped, so we cut off the brittle/cracked part and reconnected the hoses, etc.

Drove it to above 25mph, set the cc and voila, it works now.

Thanks for all the advice.
 

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Discussion Starter #7
Oh, yeah. We removed the piece of hose that was lodged above the hose connections.

Didn't say that before, did I?
 

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Discussion Starter #8
Notice something while doing this repiar.

The cruise control disengages automatically when the car speed drops below 25 mph.
 
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