high-pitched squeal coming from pass. front wheel
 

I have had this issue for a while, but it has gotten much worse. On a long road trip (12 hrs.), about 5 hrs into it, the squeal/rattle started to occur. It only happened when I turned left or hit the brakes from a certain speed, but now it does it on highways going straight, until I get on the gas pedal. When I get off the gas pedal, it starts back up. The dealer said it was my inner brake pad being low, but this was 2 months ago and I still have a good amount left on the outer pad and of course, no wear sensor light. Could it be the spindle or something? I really need to figure it out though... car is going out of warranty in 2 months!

1) is it a squeal or a rattle?
2) The brake pad doesn't have to trip the sensor to be squealing. It will trip the sensor when there's almost bare metal on the pads.
3) What makes you think it's the spindle?

I have no idea what it is.... it's a squeal/ really fast ticking. How could it be the inner pad if the noise only occurs when turning left, braking at speeds below 20mph, and at highway speeds 65 mph & over when i'm not accelerating.

anyone have any input on this?

Sounds like the brake rotor/disc backing plate is bent - possibly by a rock or stone that flew up along your road trip - and is now rubbing against the rotor. This has happened to me before. Sounds like a metal on metal high pitched scraping noise. You can easily bend it back either by hand or using some pliers. Easiest thing would be to pull the wheel to inspect it closely.

Agreed. Sounds like a pad is rubbing the rotor. Try pulling it off and cleaning it.

but why would it start rubbing at 65+ mph?

Air pressure making the difference in the 1mm space between the backing plate and rotor. Don't forgot you also have brake cooling ducts that route the air from the front of the truck to the brakes.

take the wheel off and inspect the situation. that solves a lot of problems

This is an excellent point. Also, I dealt with an issue on my CLK where I would get the squeal only upon making a left turn, and only 1 in every 5-6 turns. Still, it turned out to be the brake pad.