cruise control

[gore349]

I cannot figure out how to fix my cruise control, I just bought the car and I cannot find the cruise servo, I have replaced several vacuum lines I NEED HELP, I dont want to take it to a dealer and the car is in awesome condition, what can I do ?

It has not worked for me since day one nayone know what I can check, Does it run off a fuse?

Please help.
gore349

[gbeeley]

What year is the car?

A few ideas -

- there was a known problem on certain LeSabre years (I think late 80s / early 90s) dealing with the cruise control brake switch, where the switch would go bad and (I think) not allow cruise to engage at all.

- when I got my car the cruise servo had a problem with one of its solenoids sticking, problem was that cruise would engage for maybe 5-10 minutes and then drop out. Disassembling, cleaning, and lubricating the servo assembly solved the problem.

- on my '91 the cruise servo is bolted to the top of the transmission, has two vacuum lines going to it, and has a cable going from it to the throttle, plus a wire connector for the two solenoids inside.

[gore349]

its a 1994 buick lesabre. I appreciate your reply however, I looked at the top of the brake pedal but Im a big guy and it looks like a jungle under the dash. any hints on what exactly to look for, when looking for the servo?

Thank you so much

gore349

[amplifier28]

I have a 1995 Lesabre. The cruise control has never worked either since day one. Any suggestions on what need to be repaired?

[HotZ28]

Does your speedometer work correctly? The cruise control servo is controlled with input from the VSS to the PCM to regulate voltage to the servo motors. Sounds complicated, however is very simple. The VSS is located in the transmission and sends very small voltage siginals to the PCM based on speed. The PCM interputs the VSS siginal voltage and sends a set voltage to the servo to hold the servo motor at a set voltage until it is changed by hitting the brake or changing the set point. You could have a bad VSS, a bad wire from the VSS to the PCM, no voltage from the PCM to the servo, or a bad servo motor.

[amplifier28]

My speedometer does work correctly.

[HotZ28]

Ok, eliminate the VSS and go to step two, Wiring from the VSS to the PCM. you will have varible voltage coming out of the VSS going to the PCM based on speed. The wheels have to be off the ground and turning in order to check this. One other thing I failed to mention, is your curise set switch. If the off-on switch is broken in the off mode, nothing works!

[amplifier28]

There is a normal audible clicking sound when I move the switch from off to on on the cruise control switch. Do not know if the switch is functioning or not. By the way, the passing gear does not engage either. Do not know if this helps to find solution.

[gore349]

all jokes aside, at least you get a clicking noise mine wont do crap, do you know if their is a fuse on the panel for the cruise?

[HotZ28]

The cruise circuit does not have a fuse. You need to check your VSS with a scanner that can give live updates from any output sensor. If you have a stored code, find that first.

The scanner I use monitors outputs from everthing that gives input to the ECM. If any part of a system fails, it will let you where and what to look for. I take the car for a drive with the scanner hooked up and watch the sensor outputs under varying conditions.

[gore349]

Thats sweet well i would imagine those computer arent something you can buy at Wal Mart for 19.99, so I think I will take it to my buddys shop and have him pin it out on his puter.

Thanks for everything

Gore349
Sainte Genevieve, MO

[HotZ28]

Without knowing where the problem originates, it is hard to diagnose. If you don't like the time and cost of changing parts, you need to go for the scan. Let us know what codes you find.

[gore349]

Will Do

[Flatrater]

Your cruise control is fused. Every circuit on the GM cars is fuse either using a fuse or a fusible link except for the main starter wire.

The 94 Lesabre doesn't have much in the way of scan data, so a scanner will be of very little use. But all the scan data is in the PCM.

To find your servo look at your throttle body. You will see 2 cables attached to your throttle plate. One is your gas pedal and the other is your crusie cable. Follow the cruise cable to the other end. That is your servo.

[HotZ28]

A link from another forum concerning Cruise switches. I know on Chevy's the switch is somwhat a common problem.

http://www.buickforums.com/forums/showthread.php?t=314