'03 Durango cruise control will not set
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Start with the basics, check fuse... also ask yourself....DID I DO ANY underhood work recently. Check the vacuum lines under the hood, especially around the throttle body. Look for cracks, tears, missing, disconnected..etc.. Another possibility and rather rare but it can happen. The Brake light switch..it is fairly sensitive and if it fails even though the brake lights will come on, the switch maybe stuck and trick the cruise sensor to thinking that the brake lights are on and not activate. Another symptom of this is the brake lights might always be on which in istelf can be dangerous but these two areas might be a good starting point. The brake light switch I can speak from personal experience. Different vehicle but same concept, once I replaced the switch I had no problems with the cruise after that.