On my 2003 Impala the cruise control doesn't slow you down, only speed you up. I thought they fixed this on the 2004, but I drove a 2007 today and it didn't slow the car down on a mild rolling hill when set at 27mph. Is this a technology that doesn't exist on Impalas or was this one broken? Definitely keeps tickets away in 25mph zones and on highways, so it's critical to me - I won't buy the car if it's bad technology. Help!
nan

 

You have to tap it to slow you down, not hold it. It will slow you down in 10mph increments. Every tap is 1mph.

 

Tap the cruise control button? Or tap the brakes? I'd like it to contol the speed on it's own without user input....what's the point of having to control it yourself?

 

Aight i re-read your post. if your going downhill with the cruise set on lets say 30mph, the car will speed up, thats just gravity at work. Ford, Dodge, Chevy Honda Mistubishi, all do that with cruise set down hill. Toyota may speed up on you going uphill LOL.

As for the tapping, I don't know about the 03, but the 07 should have a cruise control setup similar to mine, I meant to slow down the cruise control, you have to tap the - sign.

 

Yep, on a downhill it will somply shift to neutral and not slow you down. I never drove one that would. Now with the tow/Haul mode on a truck when you hit the brakes, it will down shift and stay in the lower gear untill you give it some gas.

 

My 04 burb slows me down going down hills. As long as it isnt to steep. I set it for 60mph it keeps me within 3 mph going up or down hills.

 

Cruise controls DO NOT apply the brakes or downshift for you. It is not a software glitch or hardware problem. it is normal design. when the cruise is set, its function is to either apply the accelerator pedal, or do not app accelerator pedal.
so like nauticstar87 said, gravity is pulling you down causing you to speed up

 

My Mercedes cruise control breaks going downhill. After just getting a speeding ticket in my '08 Impala, I feel grateful for this post--I thought it needed repair. Seems not to be a thing with the Impala!