Cruise Control increases speed on its own

Retired Bob · November 27, 2018

2014 5.3 Double Cab, no tunes:

Traveling on the interstate in Georgia (hilly highway).

Cruise Control set to 73mph.

After about a ½ hour on the road and going up an incline I noticed the speedometer reading over 80mph and still increasing. I pushed the cruise control 'decrease' button on the steering wheel – it showed a decrease of 1mph but the speedometer did not show any decrease.

I verified the speed on my Garmin GPS – same as showing on the speedometer.

I disengaged the cruise control and used the gas pedal. About 10 minutes later I tried the cruise control again at 73mph and it increased speed on it's own again.

I stopped for fuel and after starting the truck again (on a flat/level road) the cruise control behaved properly for the next 2 hours as I change speed up and down using the steering wheel buttons and turned cruise control ON and OFF as needed.

Any ideas on what could cause this cruise control issue? The auto speed increase to above 80mph was so smooth I wasn't aware of the increase until I noticed the speedometer. I'm out of warranty and don't really want to pay the dealer a 'diagnostic fee' and hear "We can't find any problem".

BigBadSierra · November 27, 2018

Are you still running stock tires that's the first question?

Mine will throw in extra going up hills but stays around the set speed.

What does the display say for the set cruse speed is that changing.

I had bad button on a 2003 Cutlass it would do what you are stating.

I replaced the column arm for like $60 and it corrected it.

Retired Bob · November 27, 2018

Stock tires. The set speed stays at 73mph while the speedometer climbs from the 73 set speed to 80+ speed. I asked the dealer lead mechanic this morning and he said he has never heard of this issue but did not think there was any reason not to drive the truck unless I found it happening again.

aseibel · November 27, 2018

This may be a silly question, but you weren't just coasting downhill when this happened were you?

I think most cars are allowed to coast faster than the set speed, but once you reach flat ground again, you will decelerate until you again reach the "set speed"