Too mundane to put in GQ, but move if you will.
When going downhill, the cruise control often brakes to maintain the speed. I assume the break lights come on. Yes?
No car I’ve ever driven has had a cruise control able to apply the brakes. The best it can do to slow down is to throttle back to idle and coast.
I can’t answer the OP’s question but my ex-wife’s RAV4, when holding down the “set” button which also decelerates the car (in most cars this is similar to taking your foot off the gas) would apply the brakes after a few seconds…or rather did something that actively slowed the car down. I assume it was the brakes. I remember being able to hear something that sounded pneumatic happening when it activated.
Well, my 2007 Jag does. As did a Honda Accord I owned 15 or so years ago. The drivers manual even cautions not to keep your foot under the brake pedal, as it is depressed when going down steep hills. That is why I assume the lights go on.
On the cars I’ve seen, the brake light comes on due to a switch wired right to the brake pedal (which also controls stopping the cruise control and the park interlock to the best of my knowledge). Based on that, if the CC is actually moving your brake pedal, I assume it would turn your lights on. The only way I could see it not turning the lights on is if the lights were controlled by the car’s computer and the CC overrode.
In my car it feels like the engine does all the braking, it doesn’t feel at all like the brakes are being applied. Maybe I need to find some steeper hills for testing purposes. Done at night it should be easy to see if the brake lights are activated.
Do you have a high-end/luxury car that may have a feature years before the rest of the models get it? I’ve never seen it apply the brakes. Doesn’t cruise control only keep you from going under the set speed? You’ll go over whatever the cruise control is set at when doing down a hill.
The current model automatic Corollas (had 2 as rentals) will downshift in an attempt to maintain your set cruise speed when travelling downhill. Even when not on cruise control, if you tap your brakes.
Nifty.
We’ve had a number of different vehicles over the years with cruise control, and I’m unaware of any of them ever deliberately braking. If I decide to speed up to pass or something, I just use the gas pedal, and when I’m done, I release and near as I can tell, the car just coasts till it’s back at the preset speed.
And hitting the brakes disengages cruise, at least in my cars it did, so if it braked, it’d be cutting itself off, right? My reference points are a Scion, 2 Jettas, a Crossfire, an Aerostar, a Corvette, a New Beetle, a MX5, a PT Cruiser, a Mazda 626, an Escort, a GMC van, and my daughter’s Fiesta. Do we just have cheapie cruise controls?
Your standard cruise control does not put on the brakes on any car I am familiar with. It will close the throttle and allow engine braking. Engine braking does not turn on your brake lights.
With that said starting in about 2006 or thereabouts adaptive cruise controls started to appear. With this type of system there is a forward looking radar unit that “sees” the road ahead. If you are approaching the car ahead it will back off the throttle to maintain a safe following distance (and yes it lights up the brake lights when doing so). It can also apply the brakes when going down hill.