Cruise control won't engage. Light goes on the switch when you press it but cannot set the speed, CRUISE won't light up on the dash.

step 1
Remove the left sound insulator
step 2
the stop switch is here, way way up top
use flash light to see it.
it is there.
top of pedal it is there. SM books step1.

buy the service manual.?
if the switch ever sticks on , cruise ENDS
it is a NO, switch normally open contarts
no calibration is stated so its PnP

brake control switch ???? Define brake control switch ? Do you mean the switch on top of the brake pedal ? Brake light switch ? bake symbol stays??? Assume you mean brake symbol ? This is why you should have taken to a qualified repair shop. You probably have no idea as to how the cruise works . Your vehicle's cruise control is computer controlled . Vehicle has electronic throttle control , do you know what that is ? Before i get to technical , is the air bag light lit on the instrument cluster ? When you turn on the cruise does the cruise light turn on ? Taking the vehicle to a qualified repair shop that has a factory or professional type scan tool an checking for DTC'S - diagnostic trouble codes should be the first step in the diagnostic process . Not guessing an replacing parts . Do or did the brake lights work before or after switch replacement ? If so the switch wasn't bad.

The body control system consists of the body control module (BCM), communications, and various input and outputs. Some inputs, outputs and messages require other modules to interact with the BCM. The BCM also has discrete input and output terminals to control the vehicle's body functions. The BCM is wired to the GMLAN high speed serial data buss and the GMLAN low speed serial data buss and acts as a gateway between them. If the BCM does not communicate the vehicle will not start due to the inability of the engine control module (ECM)/powertrain control module (PCM) and theft deterrent module (TDM) to communicate without the BCM providing the gateway function.

Cruise Control Description and Operation
Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions at speeds above 40 km/h (25 mph). Steep grades may cause variations in the selected vehicle speeds.
The following are the main components of the Cruise Control System:
• The accelerator pedal
• The stop lamp switch
• The body control module (BCM)
• The cruise control switches
• The engine control module (ECM)
• The throttle actuator control (TAC) motor
• The vehicle speed sensor (VSS)

The body control module (BCM) monitors the signal circuit of the cruise control switches. The BCM relays the cruise control switch status to the engine control module (ECM) via the GMLAN serial data circuit. The ECM uses the status of the cruise control switch to determine when to capture and maintain the vehicle speed. The ECM monitors the vehicle speed signal circuit in order to determine the desired vehicle speed. The ECM uses the throttle actuator control (TAC) motor in order to maintain the vehicle speed. For further information on the TAC System, refer to Throttle Actuator Control (TAC) System Descriptionfor the 4.3L engine or Throttle Actuator Control (TAC) System Description for the 4.8L, 5.3L, 6.0L, 6.2L or 7.0L engines.
Voltage is supplied to the cruise control switch via the steering wheel control switch reference voltage circuit supplied by the BCM. The cruise control function switches are arranged in a resistive ladder design, with each cruise control function switch having a different resistance value. The BCM detects a specific voltage value that is associated with the cruise control function switch being activated. When the normally open cruise control on/off switch is turned ON, the switch closes and the BCM supplies a ground to the cruise control switch ON indicator circuit as it becomes illuminated. The BCM sends a GMLAN serial data message to the ECM indicating that the on/off switch is active. Similarly, when the normally open + RES switch or the normally open - SET switch are pressed, the switch closes and the BCM detects the predetermined voltage signal on the cruise control set/coast and resume/accel switch signal circuit. The BCM sends a GMLAN serial data message to the ECM indicating that the + RES switch or the - SET switch is active. To engage the Cruise Control System, ensure that the vehicle speed is above 40.2 km/h (25 mph), turn the cruise On/Off switch ON and momentarily press the - SET switch. The ECM will engage the Cruise Control System and record the vehicle speed. The ECM sends a GMLAN serial data message to the driver information center (DIC) in order to illuminate the CRUISE SET TO ### message. The ECM sends a GMLAN serial data message to the instrument panel cluster (IPC) in order to illuminate the Cruise Engaged indicator in the IPC. The - SET switch and the + RES switch will remain inactive when the BCM has not received the predetermined voltage signal from the on/off switch. Pressing the accelerator pedal, while the Cruise Control System is engaged, will allow the driver to override the Cruise Control System in order to accelerate the vehicle beyond the current set vehicle speed. When the accelerator pedal is released, the vehicle will decelerate and resume the current set vehicle speed. The driver can also override the current set vehicle speed via the - SET switch and the + RES switch. When the Cruise Control System is engaged, pressing and holding the - SET switch will allow the vehicle to decelerate from the current set vehicle speed without deactivating the Cruise Control System. When the - SET switch is released, the ECM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the Cruise Control System is engaged, momentarily pressing the - SET switch will allow the vehicle to decelerate at 1.6 km/h (1 mph) increments for each time that the - SET is momentarily pressed, with a minimum vehicle speed of 37 km/h (23 mph). Pressing and holding the + RES switch, when the Cruise Control System is engaged, will allow the vehicle to accelerate to a greater vehicle speed than the current set vehicle speed. When the + RES switch is released, the ECM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the Cruise Control System is engaged, momentarily pressing the + RES switch will allow the vehicle to accelerate at 1.6 km/h (1 mph) increments for each time that the + RES switch is momentarily pressed, with the maximum acceleration total of 16 km/h (10 mph) over the current set vehicle speed. Momentarily activating the + RES switch will recall the previous vehicle speed, after the cruise control system is disengaged by pressing the brake pedal or by activating the CANCEL switch.

Very highly doubtful that you could fix this .

There is a vacuum leak in the hose that goes from the control unit to the engine intake manifold.

problems with cruise control include , clutch switch, brake switch , low road speed , control module , speedo sender unit
make sure that all those items are adjusted as one one will stop the cruise control from engaging

It is HVAC 1fuse #39 in the rear fuse block ,this powers the on/off switch for cruise control ! Fuse Block - Rear Beneath the left rear seat. What engine does it have ? 4.2 L or 5.3 l There is no vacuum involved in the operation of the cruise control ! Your vehicle has electronic throttle control .
Cruise control is a speed control system that maintains a desired vehicle speed under normal driving conditions at vehicle speeds above 40 km/h (25 mph). Steep grades may cause variations in the selected vehicle speeds.
The following are the main components of the Cruise Control System:
?€¢
The powertrain control module (PCM)

?€¢
The On/Off switch

?€¢
The Resume/Accel switch

?€¢
The Set/Coast switch

?€¢
The TCC brake switch

?€¢
The stop lamp switch

?€¢
The throttle actuator control (TAC) motor

?€¢
The vehicle speed sensor

Cruise Control Engaged
The cruise control system will engage and adjust the vehicle speed based on the activation of the following cruise control switches:
?€¢
On/Off

?€¢
Resume/Accel.

?€¢
Set/Coast

The cruise control switches are located on the multifunction/turn signal lever.
The powertrain control module (PCM) monitors the signal circuits of the cruise control switches in order to determine when to capture and maintain the selected vehicle speed. The PCM uses the throttle actuator control (TAC) module motor in order to control the vehicle speed. For further information on the TAC System, refer to Throttle Actuator Control (TAC) System Description in Engine Controls - 4.2 L.
Ignition positive voltage is supplied from the 10 ampere HVAC 1 fuse to the cruise control switch via the ignition 3 voltage circuit. When the normally open cruise control On/Off switch is turned On, the switch closes and the PCM detects a high signal voltage on the cruise control on switch signal circuit. When the normally open Set/Coast switch is pressed, the switch closes and the PCM detects a high signal voltage on the cruise control set/coast switch signal circuit. To engage the cruise control system, turn the On/Off switch On and momentarily press the Set/Coast switch. The PCM will confirm that the cruise control enable criteria has been achieved. The PCM will engage the cruise control system and record the selected vehicle speed. The PCM sends a class 2 message to the instrument panel cluster in order to illuminate the cruise control indicator. Pressing the accelerator pedal, while the cruise control system is engaged, will allow the driver to override the cruise control system in order to accelerate the vehicle beyond the current set vehicle speed. When the accelerator pedal is released, the vehicle will decelerate and resume the current set vehicle speed. The driver can also override the current set vehicle speed via the Set/Coast switch and the Resume/Accel switch. When the cruise control system is engaged, pressing and holding the Set/Coast switch will allow the vehicle to decelerate from the current set vehicle speed without deactivating the cruise control system. When the Set/Coast switch is released, the PCM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the cruise control system is engaged, momentarily pressing the Set/Coast switch will allow the vehicle to decelerate at 1.6 km/h (1 mph) increments for each time that the Set/Coast is momentarily pressed, with a minimum vehicle speed of 37 km/h (23 mph). When the normally open Resume/Accel switch is activated, the switch closes and the PCM detects a high signal voltage on the cruise control resume/accel switch signal circuit. Activating and holding the Resume/Accel switch, when the cruise control system is engaged, will allow the vehicle to accelerate to a greater vehicle speed than the current set vehicle speed. When the Resume/Accel switch is released, the PCM will record the vehicle speed and maintain the vehicle speed as the new set vehicle speed. When the cruise control system is engaged, momentarily activating the Resume/Accel switch will allow the vehicle to accelerate at 1.6 km/h (1 mph) increments for each time that the Resume/Accel switch is momentarily activated, with the maximum acceleration total of 16 km/h (10 mph) over the current set vehicle speed . Momentarily activating the Resume/Accel switch, after the cruise control system has been disengaged by pressing the brake pedal, will recall the previous set vehicle speed that is recorded in the PCM.

have you got a bad antilock brake sender maybe a code scan at autozone then google what codes you find include our car in search term and code

Try checking the small switch at the top of the brake pedal. There may be two one for brake lights and one for the cruise control. To ascertain what is what, pull one wire off and see if brake lights work. If not, then the other switch controls the cruise control disconnect and engage..I you have a DC test light check to see if power is on on both side of the switch with brake pedal up. If so, depress pedal and check power on the other side there should be none, if there is the switch is defective.

Is you brake light working properly?

The cruise-controls have 2-buttons that must be activated before it gets the car going when you remove your foot off the gas-pedal.
The cruise button is essentailly a switch that turns 'on' the cruise servo-motor that tells the sytems that you wants to use it, so it gets ready.
There are other three switches on the right-side of the steering wheel namely: resume accel; cancel; set decel.
To get your car to cruise: you must steady your speed and foot on the gas-pedal. You cannot just press the switches and expect the car to cruise. It takes about two-to-three seconds for the system to respond to a set cruising speed.
How to do it: accelerate to a speed of about 30-mph. Press the 'cruise' button on the dash first. Next you press 'set decel' button. This will turn 'on' the cruise control light on the instrument panel. Then wait a second or three and you would feel the cruise engagement. Any touch on the brake pedal will slow down the car and turns the cruise off. The 'cancel' button turns off the cruise light on the instrument panel.
If you hit the brake-pedal at any time for any reason, and you would like to continue cruising again, simply press the 'resume accel' button.
The cruise system works in conjunction with the braking system of the car. So all major parts of the braking system must be in good condition, otherwise the cruise system could shut off itself.