Cruise Controll?
Melting Slicks
Joined: Sep 2008
Posts: 2,376
Likes: 111
From: Cherokee National Forest TN
The simple things first.
Speedometer working properly?
Check the mechanical linkage, pull the lever @ the cruise servo to insure it operates the throttle.
Engine running: remove the large vacuum hose from the cruise servo & check for vacuum. No vacuum = fix that problem.
If it has vacuum: shut off engine, use a mighty vac to pull vacuum on the servo this will test the integrity of the servo & the pedal switch(s)
Will not hold vacuum=repair the faulty component.
Holds vacuum = electrical system.
Check the fuse.
If all of the above checks ok you need a FSM to check the electrical.
A word of caution when following the FSM.
Check the servo electrical first.
Skip the step about checking for power @ the cruise module, save it for last.
After checking the servo if ok go to the steering colum connector to check for power & switch operation.
Speedometer working properly?
Check the mechanical linkage, pull the lever @ the cruise servo to insure it operates the throttle.
Engine running: remove the large vacuum hose from the cruise servo & check for vacuum. No vacuum = fix that problem.
If it has vacuum: shut off engine, use a mighty vac to pull vacuum on the servo this will test the integrity of the servo & the pedal switch(s)
Will not hold vacuum=repair the faulty component.
Holds vacuum = electrical system.
Check the fuse.
If all of the above checks ok you need a FSM to check the electrical.
A word of caution when following the FSM.
Check the servo electrical first.
Skip the step about checking for power @ the cruise module, save it for last.
After checking the servo if ok go to the steering colum connector to check for power & switch operation.
Pro
Joined: Oct 2009
Posts: 679
Likes: 0
From: vero beach florida
The simple things first.
Speedometer working properly?
Check the mechanical linkage, pull the lever @ the cruise servo to insure it operates the throttle.
Engine running: remove the large vacuum hose from the cruise servo & check for vacuum. No vacuum = fix that problem.
If it has vacuum: shut off engine, use a mighty vac to pull vacuum on the servo this will test the integrity of the servo & the pedal switch(s)
Will not hold vacuum=repair the faulty component.
Holds vacuum = electrical system.
Check the fuse.
If all of the above checks ok you need a FSM to check the electrical.
A word of caution when following the FSM.
Check the servo electrical first.
Skip the step about checking for power @ the cruise module, save it for last.
After checking the servo if ok go to the steering colum connector to check for power & switch operation.
Speedometer working properly?
Check the mechanical linkage, pull the lever @ the cruise servo to insure it operates the throttle.
Engine running: remove the large vacuum hose from the cruise servo & check for vacuum. No vacuum = fix that problem.
If it has vacuum: shut off engine, use a mighty vac to pull vacuum on the servo this will test the integrity of the servo & the pedal switch(s)
Will not hold vacuum=repair the faulty component.
Holds vacuum = electrical system.
Check the fuse.
If all of the above checks ok you need a FSM to check the electrical.
A word of caution when following the FSM.
Check the servo electrical first.
Skip the step about checking for power @ the cruise module, save it for last.
After checking the servo if ok go to the steering colum connector to check for power & switch operation.
You did check the fuses??
1) Check the hose coming from the engine for vacuum.
2) Check hose going to brake pedal.
3) check release valve on pedal, sometimes it leaks.
4) Check CC for power.
5) check switch on stalk.
Right near the battery, is where both my hoses gave way, guessing the battery fumes did them in.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
The last few cruise problems we diagnosed on the Forum (including mine) turned out to be the electrical switch on the brake pedal. If the vacuum check valve is bad it will probably affect the A/C vents from working correctly.
But if the check valve is OK, then the switch is a likely prospect.
If you have a clutch, it has a switch to.
Also check the fuse and the switch on the turn signal.
Check these links for additional information.
http://forums.corvetteforum.com/c4-t...-question.html
http://forums.corvetteforum.com/c4-t...-for-94-a.html
But if the check valve is OK, then the switch is a likely prospect.
If you have a clutch, it has a switch to.
Also check the fuse and the switch on the turn signal.
Check these links for additional information.
http://forums.corvetteforum.com/c4-t...-question.html
http://forums.corvetteforum.com/c4-t...-for-94-a.html
Last edited by pcolt94; Mar 10, 2010 at 07:08 AM.
Le Mans Master
Joined: May 1999
Posts: 6,517
Likes: 1,304
From: Windermere FL
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Let me give a quick over view of the reality of actual problems. From what I have done, seen and heard, the major components are not on the top of the list of defective parts. The cruise control module under the right side of the dash is a real convenient point to make measurements from but is a bear to get to.
The solenoids in the servos can be checked with resistance to see if their open. It's a basic check only. Operation of solenoid cannot be verified using this check.
Most of the actual problems have been bad vacuum hoses or connections, the check valve, electrical connections or the dis-engage switches on the brake (or clutch). The switch on the brake is a triple switch that has the cruise switch in it as well as the brake light and lock-up (TTC) switch.
The switch can be removed, taken apart and contacts cleaned if corroded. The contacts also come out of the switch body, it's beautiful. Save you $50 if you had to buy one.
But most of the time the problem may seem difficult, but the cure is simple.
If the problem can't be found simply or by poking around, then selected points have to be monitored (taking measurements) as the car is driven and evaluate the results. Actually have to troubleshoot it as I did for mine.
The solenoids in the servos can be checked with resistance to see if their open. It's a basic check only. Operation of solenoid cannot be verified using this check.
Most of the actual problems have been bad vacuum hoses or connections, the check valve, electrical connections or the dis-engage switches on the brake (or clutch). The switch on the brake is a triple switch that has the cruise switch in it as well as the brake light and lock-up (TTC) switch.
The switch can be removed, taken apart and contacts cleaned if corroded. The contacts also come out of the switch body, it's beautiful. Save you $50 if you had to buy one.
But most of the time the problem may seem difficult, but the cure is simple.
If the problem can't be found simply or by poking around, then selected points have to be monitored (taking measurements) as the car is driven and evaluate the results. Actually have to troubleshoot it as I did for mine.
Pro
Joined: Oct 2009
Posts: 679
Likes: 0
From: vero beach florida
Let me give a quick over view of the reality of actual problems. From what I have done, seen and heard, the major components are not on the top of the list of defective parts. The cruise control module under the right side of the dash is a real convenient point to make measurements from but is a bear to get to.
The solenoids in the servos can be checked with resistance to see if their open. It's a basic check only. Operation of solenoid cannot be verified using this check.
Most of the actual problems have been bad vacuum hoses or connections, the check valve, electrical connections or the dis-engage switches on the brake (or clutch). The switch on the brake is a triple switch that has the cruise switch in it as well as the brake light and lock-up (TTC) switch.
The switch can be removed, taken apart and contacts cleaned if corroded. The contacts also come out of the switch body, it's beautiful. Save you $50 if you had to buy one.
But most of the time the problem may seem difficult, but the cure is simple.
If the problem can't be found simply or by poking around, then selected points have to be monitored (taking measurements) as the car is driven and evaluate the results. Actually have to troubleshoot it as I did for mine.
The solenoids in the servos can be checked with resistance to see if their open. It's a basic check only. Operation of solenoid cannot be verified using this check.
Most of the actual problems have been bad vacuum hoses or connections, the check valve, electrical connections or the dis-engage switches on the brake (or clutch). The switch on the brake is a triple switch that has the cruise switch in it as well as the brake light and lock-up (TTC) switch.
The switch can be removed, taken apart and contacts cleaned if corroded. The contacts also come out of the switch body, it's beautiful. Save you $50 if you had to buy one.
But most of the time the problem may seem difficult, but the cure is simple.
If the problem can't be found simply or by poking around, then selected points have to be monitored (taking measurements) as the car is driven and evaluate the results. Actually have to troubleshoot it as I did for mine.
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Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
I will consider myself as “corrected” as far as the location on the CC module. I just assumed the 92-93 was the same as my 94 which is really buried up under there. If interested, take a look at my second link above to get an idea. Darn thing is under the SIR module, a mess to get out.
