[MrChicken]

I've noticed an annoying noise coming from the left hand side of the dash when using ACC at slower speeds. I was in some slow traffic on the highway and a loud relay click sounded when the Ascent transitioned from braking to acceleration and vice versa. I've seen this mentioned in the Outback forums but no resolution or explanations were given. Anyone else hearing this?

 

[GaryInMI]

I have not noticed this sound nor has my wife ever mentioned hearing this during the 5,000+ miles we have driven with ACC engaged in every traffic scenario.

That being said, my hearing is pretty bad and we usually have music playing.

Maybe your relay is extra noisy.

 

[Robert.Mauro]

There is no relay in the car associated with ACC.

It is possibly the normal function of your air conditioner which makes an occasional tock/click sound.

Alternatively, you could be hearing the brake pedal moving when the car is braking.

 

[James B]

I've noticed an annoying noise coming from the left hand side of the dash when using ACC at slower speeds. I was in some slow traffic on the highway and a loud relay click sounded when the Ascent transitioned from braking to acceleration and vice versa. I've seen this mentioned in the Outback forums but no resolution or explanations were given. Anyone else hearing this?

I noticed this to the other day while using ACC in stop'n-go traffic. Maybe brake light relay, or pedal switch? Not worried about it though.

 

[MrChicken]

It sounds just like the rear wiper relay noise on my Forester. It doesn't sounds like it's coming from the floor, just the left side of the dash between the steering column and driver's door. I will try it again with the A/C turned off.

 

[Radzer0]

I noticed this to the other day while using ACC in stop'n-go traffic. Maybe brake light relay, or pedal switch? Not worried about it though.

I also believe it’s something with the brake lights. That’s when I hear it click usually when going downhill and the speed builds up too much.

Your not alone at hearing it tho. It could also be a system to actually activate the brakes.

 

[MrChicken]

There is no relay in the car associated with ACC.

It is possibly the normal function of your air conditioner which makes an occasional tock/click sound.

Alternatively, you could be hearing the brake pedal moving when the car is braking.

I tried it again with the A/C off. It defintely happens when the brakes engage and disengage. I'm going with Robert's suggestion that it's the mechanical action of the brake pedal.