Our 2005 trailblazer's cruise control stopped working where is the fuse or does it even have oneit does not say on the fuse box lid..

Here is the fuse box diagrams for the 2 different engine options...and the 2 different box locations
Buick Rainer 2003 2006 fuse box diagram Auto Genius
HOWEVER ... I do not think there is an associated fuse for cruise control. That function is totally run from your on board computer (ECM). What can make the cruise not work is if any fault codes have occurred... Has your check engine light come on?
Some people with the same problem (that do not have an OBDll scanner to read or clear codes) disconnected their battery to reset the ECM. The cruise control then worked .... but if the root cause of the fault is not fixed ... then the same thing will likely happen again
Helpful?
Good luck with your troubleshooting

All of the fuses are in the box under the hood. If you look at the inside of the lid of the fuse box it has the layout of the fuses / relays and their purpose.

check cruise control fuse and check the brake lights see if brake light working because the brake light switch will deactivate cruise control when brakes is applied.if brake lights dont work either fuse blowed or switch bad.if all is good have vechicle code scan because cruise control control by PCM and vechicle speed sensor and thottle actuator control motor.

I would check the turn signal switch. The cruise and turn signal are on the same switch. The brake lights go through the switch before going to the brake lights. And the turn signals don't work with the ignition off.

Does the cruise control lights come on when you select it? If it doesn't then you may want to check the fuse(s) that give the system power. If the fuse is blown then try replacing it. If it blows again when you try to use the cruise control then the unit it self may be bad and need replacing. You can find the fuse box location and the right fuse for it in the owners manual of the car.

I don't believe the two problems are related. For the interior lights check fuses #4 and #40 in the rear fuse panel. Also make sure you didn't inadvertently press the interior light disable button on the left side of the dash.
The cruise control can be disabled for several reasons, such as the check engine light being on, brake lights on continuously, vehicle speed sensor defective or a defect in the turn signal stalk. A technician with a high end scan tool can diagnose the problem easily.

There is actuly 2 differant fuse #12 the brake fuse #12 10 amp and fuse #1 the stop and haz 20 amp .But neighter are likely the problem . There is another brake switch for the cruise control called the TCC brake and cruise control relese switch that tells the transmission when the brake is applyed and shut of the cruise control . This is more likely the problem its up under the dask near the steering colluom follow the wires from the main brake switch on the pedel if you have a standard then it will run through the clutch switch as well .Fuse #12 also controls the muilty function switch but fuse #1 is the brake input switch . So if the lights and blinkers work i would look at the TCC brake switch first thank you

I take it that it's not working? 1 thing to keep in mind...if there are any check engine codes stored in the computer, te cruise control will be disabled. When this code is cleared out, the cruise control will work again.

The BRAIN BOX which is known by most car owners controls the throttle boy accellerations control when engaging the cruise control on. If your fuses are good I recomend have the servo (brain box) checked

Sounds like you need new fuses. Normally you'd find the fuse box under the hood of the car, under the dash on the passanger side, or under the steering wheel. The fuses should say how many amps it requires and what it controls, then replace them. But if your cruise control still isn't working after you've changed fuses, then it might be vacuum operated and need a new hose.