OT: '93 Buick Regal cruise control gave won't turn off...

I had a little excitement this weekend... usually I don't drive this car in the winter and it has 102k mostly highway miles. I recently had a remote starter installed. I also had an oil leak on the back side of the block repaired (which required much of the intake to be removed. I don't think I used the cruise since either of these things were done.

On Friday I started my trip to see my dad who isn't doing too well and recently had a small stroke. (He'll be 98 in April.) I engaged the cruise and all seemed to be normal for about 10-15 miles. Then someone pulled in front of me and I touched the brake to disengage the cruise and it wouldn't kick out. I move the switch to off and the light on the dash went out but the cruise stayed on. (At this point it's getting a little exciting.) So I stand on the brake and it slows me down, but it still won't kick out. I take the nearest off ramp and I'm literally standing on the brake to get it to stop. After coming to almost a dead stop (the engine is now racing at 2200 rpm) after a few seconds, I slowly see the rpms drop. After that it the car was as it should be with the cruise off.

My first thought was to blame the remote starters, so I call the installers and the tech comes to the phone and says he's installed them for 20 yrs and he's never had this happen. He says they'll charge me to look at it.

So then I call the guys that fixed the leak and he says to bring it in. He takes if for a drive but I suspect he didn't drive it long enough or fast enough to have it "freeze up" or whatever is going on. He checked for vacuum leaks, etc. and says he can't see anything obvious. This is my first time with this mechanic, but is highly recommended.

I don't have a spare vehicle at the moment so I proceed on my trip. While I'm in the middle of no where with no cars around I tried it again. It worked fine for about 10-15 miles... speed up with resume, slow down with set, etc. worked fine... then it "freezed" up again. This time I pressed on the brake hard and down shift as I slow down some. It kicked off somewhere between 10-20 mph. I didn't use it again.

What's wrong here ? Is it the combo switch on the turn signal ? Computer/ecm issues ? Did one of the shops screw up something ? Cold weather/frost ? Other thoughts !?!

Thanks in advance.

Because you cannot control the action when you use it, and because it is broken, there is no assurance that it will not come "on" by its self. I would not drive it until repaired. this means analyzed and understood what is wrong, and made correct. Three separate shutoff systems failed to work: The brake switch, the Cruse Control power switch, and the stalk control. I am going to look at a circuit diagram. I suggest you look to google to see if there is an issue. Jim

I doubt, its related to previous repairs, probably related to age and temps if anything. Since you turned off the speed control with the switch and confirmed with the indicator lamp going off I would assume the problem is mechanical. I would be looking at the throttle body and linkage, cables and speed control servo for problems. Seems more like a cable, linkage or servo is binding causing the throttle plate to stick open.

Also dont forget to check the floor area around the throttle pedal, I dont know how many times I have found floor mats jamming the throttle pedal.

Sounds like your brake switch is sticking, or the linkage is binding at the throttle body. Those cruise systems are usually very dependable and easy to fix.
Good luck and God bless.

It would be interesting to see if the power is cut to the module when you switch it off. Seems like it is staying "right" just long enough for something to stiffen up in the cold. Maybe it is cutting the power but there's something sticking in the cold.

If the fuses are someplace you can reach them I would find out which one was the cruise. Take it out and drive it and pull that fuse and see if it switches off for you.

I suggest that the servo is getting stuck in the engaged position because:

1) Electrically, turning off the switch should have disengaged it. Failure to disengage at that point would tend to indicte that it is NOT an electrical problem, and point towards a mechanical problem.

2) Hitting the brake SHOULD dump the vacuum to the servo. The servo is operated by a vacuum diaphragm much similar to your power brake booster. Dumping the vacuum should cause it to immediately release the throttle. There is a vacuum dump switch on the brake linkage that you should be able to check out.

These two items pretty much rule out a vacuum or electrical problem. My vote is to replace the servo. Also check for any binding or restriction in the linkages. Overall, I would say that with 99% certainty, your problem is mechanical, and the prime suspect is the servo.

Dealt with that on a Ford about that age. Turned out to be the cruise control cable was frayed internally and would hang up sometimes.

The following Wiring info was found on the net.
If it was actually off electrically, the mechanical system under the hood might be at fault. However! If you could regulate the settings when frozen, or if the throttle was actively trying to govern the speed while "frozen" I think it needs real GM diagnosis and repair. Be safe!! Jim

Constant 12V+ Red Ignition Switch Harness or Use Hot Side of Brake
Switched 12V+ Pink Ignition Switch Harness
Ground Use Chassis Near Cruise Control Module
Hot Side of Brake Orange Brake Switch
Cold Side of Brake White Brake Switch
Tach Purple/White Multi Coil Pack
VSS Wire Dark Green B-8 on White Connector or P-13 on Purple Connector
Pulses Per Mile 4000 PPM

Excuse me while I hop on my soapbox for a minute. Not picking on you personally, but drivers in general.
Your little event proves two things- 1; standing on the brake will stop the car, no matter that the throttle is calling for power, 2; nobody teaches that in emergency, TURN THE KEY OFF!!
In the first scene, this debunks the story about so many cars that the gas stuck, I couldn't stop, even racing 100 mph down the freeway, or hitting that car stopped at a light & killing several people.
In the second scene, nobody teaches drivers to turn off the key. It should be a driver's first reaction, cut the engine off, drift to the side of the road, after it stops, figure out what to do next.
To the naysayers- turning off the key will NOT lock the steering. Any car since the late 60's have to be in park, or if stick shift push a button, before the key can turn to the lock position. As long as the engine is still turning, there will be power to the steering, after engine dies, steering will be a bit stiff, but still work. Power brake assist will be lost after the engine dies, but brakes will still work with a little extra effort.
End of rant.
Willie

During the first test, it was pretty level...

After I detected it was frozen/sticking the second time, there were a few hills. As I was going down/up hills, it would speed up/down respectively... so it clearly wasn't regulating at that point.

Also, when it disengaged, it didn't cut out all at once but gradually.

Thanks for your reply. My Haynes manual has little information and suggests taking it to a shop.

Thanks. That sounds like a possibility.

Now I need to decide if I should take it to a dealer or give an another shop a chance.

I now believe that the throttle plate could be sticking in the bore. Move the plate bu hand and see if it has dramatic resistance. Opening it should have spring tension, closing it should snap shut. Also pull on it with the link from the Cruse control diaphragm. If it has resistance, or seems to catch on its way back, it might be a lubrication issue. Check NAPA for a throttle body cleaner approved for that system. It may just be a sticky shaft that gets "set" from being at one speed all the time. Tri-Flow PTFE based spray is a good dry lube when used on shafts that do not get oiled frequently (or ever). Just be careful as others have warned. Do use the Key Off option to see if shutting down the engine will let it snap shut. Jim

The mech that did the seal work checked the linkages and couldn't find any resistance... but without the cruise the car does run fine. I ran it 250 miles today without the cruise and I didn't have a bit of trouble.

The first time it locked up, I did turn the key off. When I restarted, it went full throttle (or where ever the throttle position was when I shut it down). There's definitely something sticking though. I might have to run it again until it "locks", shut it down, and see if the throttle or whatever is stuck... it's been so darn cold up here lately (-13F right now), it might have to wait. Luckily I don't have any long trips planned.

I agree with you Willie. Another way to react is shift into neutral. With full braking and steering get the vehicle off the road then kill the engine. Over revving for a short time won't hurt.

I've always told myself to be ready to shift to neutral if I ever encounter a run away cruise/throttle situation, pull over, then shut down.

Couple of years ago I had a similar problem with a 95 LeSabre, it would speed up without having the cruise on, driving along at 55 it would slowly gain speed, put it in neutral and the engine would rev about 3000, turn it off and restart and it would be fine. Some times at an idle it would start to slowly rev, I disconnected the cruise and checked every thing, drove it half the summer with a scan tool hooked up, finally set a trouble code for a throttle sensor, replaced it and same problem only somewhat different. Long story short, I was just about ready to park it and decided to change the throttle position sensor again, and that cured it, the first one was faulty. It ran and shifted and got better mileage that it had for years, one of my kids is using it up and it runs fine. So, maybe not the cruise at all??