2018 Siverado cruise not working

[Tom Farar]

Cruise control stopped working, what is wrong? 2018 Silverado LT

[JimCost2014]

here are a few basic ways that cruise control can fail, depending on how the system is designed. You may not be able to do much about ETCS cruise control systems, but there are a few things you can check:

Brake Light Switch – As cruise control is automatically cancelled by depressing the brake, some vehicles may disengage cruise control if it cannot detect the brake light switch.

 

Brake Lights – In some systems, cruise control is disabled when a brake light is blown. Aftermarket lighting, such as LED brake light conversion, might trick the CCM into thinking a brake light is blown, as LED bulbs draw less current than incandescent bulbs.

 

Fuses and Relays – On some vehicles, fuses and relays are used to protect the cruise control actuator circuit. If the fuse is blown or the relay is faulty, the system won’t work.

 

Spiral Cable – Many vehicles mount the cruise control switch on the steering wheel. A faulty spiral cable may have an open circuit, preventing the switch from contacting the CCM.

 

Control Switch – If the internal contacts wear out, the cruise control switch may not be able to contact the CCM. This might disable cruise control completely, or it might not react to the cancel or accelerate functions.

 

Check Engine Light – On some modern vehicles, particularly those equipped with ETCS, cruise control may be disabled if there is an engine or transmission problem.

 

Vacuum leaks on this older cruise control actuator may prevent it from working. Hans Haase / Wikimedia Commons

Vacuum Leak – Some older vehicles used vacuum actuators to control the throttle body during cruise control operation. If there is a leak, such as a cracked hose or tube, the system won’t work. A vacuum leak might cause the engine to idler higher or set a fuel trim code.

 

Vehicle Speed Sensor – There are usually multiple vehicle speed sensors (VSS) on any given vehicle. The CCM might use a VSS feed from the ECM, instrument cluster, or transmission. If that signal is lost, the CCM can’t detect vehicle speed, disabling cruise control.

 

Electrical Problems – As most cruise control systems use electrical or electronic components, any diagnosis should include a thorough check of source voltage, wiring harnesses, and connectors. Anything loose or broken could disable the system entirely.

 

If your cruise control isn’t working properly, avoid using it until it is repaired. A faulty cruise control system may not cancel on demand, which will create a safety hazard for you and those around you. After assessing your cruise control yourself, take your vehicle to a trusted mechanic for a check or a couple diagnosis and repair.