do you guys have a light that comes on, in the cluster that says cruise? In my rig, ever since I've had it, I've never seen anything such as what you boys are talkin' about.

 

The 1999 does not have such a light.
Must have started putting the light in during the 2000 model year.

It is the worlds' ultimate idiot light!

"Lets see, I'm hurtling down the highway, have been for some time now, I don't have my right foot, or my left foot for that matter, mashing down on the gas peddle and yet it would appears that the vehicle is showing no signs of a slowin' down."

"This is a makin' me somewhat suspicious, I thinks I'll look at the dash for a light to see if the Cruise Control is On"

 

When my cruise control went on my van I was expecting a big repair bill but all it ended up being was the switch on the brake that cancels out the crusie when you press the brake pedal , try pulling up on the brake pedal while you are driving and see if you can engage the cruise, if this works you may be able to adjust the switches sensitivity and or you will need to replace the switch, the one for my van was only around 34 dollars CDN.

 

The cruise went out on my rig also. It worked fine and then I went to use it about two weeks later and nothing. OK here is what it was. There is a switch with two wires to it that mounts at the front of the master cylinder. It's the switch assembly speed control. Look to see if yours has brake fluid seeping out of the top of it, and if it does then it is bad. Part#F3TZ-9F924-BB. Cost 22.22. Takes maybe 5 minutes to change. Hope this helps.

 

Cool! I give that a look~! Thanks man....,,,,98

 

I would agree that the "CRUISE" idiot light on the panel does seem a tad goofy - but then to me, so does the whole concept of turning the cruise control "ON" in the first place. All the "ON" button does is enable the additional buttons. "OFF" makes sense, but you'd think the logic would be that if you are setting one of the other cruise control buttons that you probably want the system "ON". Turning the system "ON" seems redundant to me. What am I missing here?

And do you really trust a manufacturer that thinks you don't know the difference between acceleration and speed? The "set accel" button label is comical. You aren't setting the vehicle's acceleration, you're establishing a __speed__ setpoint (target) for the cruise control system.

Other than that, it seems to work just fine.

It seems to me that the tranny shift pattern is different when the system is engaged in what is otherwise the same context (throttle position, grade, load, etc.) It's as if since the system "knows" the target speed when it's engaged, it uses that to optimally shift the tranny. When the system isn't engaged, the controls of course don't "know" where you're going to wind up at with the throttle (no setpoint established). This behavior must be built into the servo loop/tranyy/engine controls - maybe saves fuel. A variation on the normal tranny shift point adaptive behavior, or maybe it bypasses the adaptively learned shift points. I suppose I could be getting fooled - that it's the same control behavior, just that the cruise control uses a throttle schedule that I never seem to match when using my foot on the gas pedal.

As far as overall throttle behavior, I've noticed that this truck more than any vehicle I've ever owned wants to keep rolling when you back off the throttle. Seems to me it's more than just the mass of the truck - it's as if the throttle system (without speed control engaged) has some inertial or integral behavior.

But, maybe it's just the vehicle's mass, it's a far heavier vehicle than any other I've owned. And with the big 17" wheels and big fat tires there's quite a bit of rotating mass.

 

I haven't had a chance to look at the truck yet, I can only hope that is what's wrong. As for the tendency for these trucks to keep going after letting off the gas, it's pure mass that wants it to keep rolling. it's alot of weight for someone who hasn't owned a large vehicle before. The large tires would help you slow down, actually. They'd cause rolling resistance and drag.,,,,98

 

Does the 97 have a vehicle speed sensor on the differential. On my 92 this sensor went out and first the cruise control went out and then the speedometer quit working and before I got home the transmission was shifting hard from 1 to 2 and dropping out of gear completely if I exceeded 2000 rpms.

 

menchar,

The accelerate function is there for the lazy people whe do not want to use their feet. Press and hold and the truck will accelerate.

JMC

 

yep, thats why it says set / accel . You can also tap it 4 times to go exactly 4 mph faster and such.

 

OK, didn't realize that the sense of the button is "SET" and "ACCEL" as opposed to "set acceleration" . I suppose I could argue that the "accel" function is really just bumping the speed setpoint up, which of course then causes the system to accelerate to get to the new setpoint. But, they needed some way to indicate the two different functions. And "increment speed setpoint" probably wouldn't work as a label Somehow I knew that bumping "coast" decrements the speed setpoint, didn't realize accel bumps it up.

I imagine the truck's affinity for rolling on with foot off the gas may also be due to the torquiness of the 5.4L engine, the 3.55 rear end, a light load, and the idle setting of the throttle. I've noticed that at idle the truck will move forward in drive. It's kind of amusing, one day I got it out on a level empty street and just let it go. Foot completely off the throttle and brake, it got up to over 5 MPH! Idle RPM around 600 I think. Seems way agressive to me to the point of almost being a safety issue. If my foot comes off the brake at an intersection, the truck's going to take off at 5 MPH. I suppose if I was loaded down it'd be a different story.

 

I know everyone's on the edge of their seat to hear my latest on cruise control and throttle issues

On the way home from work last night, I put the truck in drive on a level empty street and from a dead stop took my foot off the brake.

The truck, idling at 850 RPM, got up to a full 10 MPH

And when I got on the 101 freeway I turned on the cruise control then pushed the "coast" button. Turns out the "coast" button sets the initial speed setpoint the same way as does the "SET ACCEL" button. That is, if all you do is press coast (without having ever pressed SET ACCEL), the system will establish the speed setpoint as the current speed of the truck. So by the logic of the SET ACCEL label, the COAST button should really be labeled "SET COAST"

 

98,

Save some money here: http://www.parts.com/index.cfm?actio...nt&sfid=213843

follow collision, electrical, cruise control to servo. About $128.00

 

I want to thank you guys for taking the time to look up parts for me. I really appreciate it!! I did a thorough underhood cleaning yesterday, and before I didn't see anything out of place or anything else wrong for that matter. The sender on the master cylinder was fine. I guess it's either that servo, and/or a bad wheel switch? I think I'm going to have it diagnosed, then fix the troubled part myself. No sense throwing parts at it and wasting money I did that a few weeks back with a non flashing signal, and ended up buying a multifunction switch. Close to $80, and it was a burned out bulb My aux. signals in the bumper changed the fast flash, to a no flash at all. At least now I have lost my phantom wipers, and I know what it is when the signals won't flash on one side.,,,,98

 

If I turn my cruise on, it will accelerate past the point I set the cruise at when I'm either going up or down hills. Then after a certain point, I hear a clicking sound from the brake pedal area and it starts deacelerating.

Could this be the servo?

thanks,
josh