Can someone tell me what the wire is for that enters the front of my drivers side brake caliper? Thanks to all.

 

That's the brake pad sensor. When the pad wears down, the sensor breaks contact, and the car tells you to service your brakes.

 

That doesn’t need to be installed back into the pad, just zip tie it up and out of the way. It isn’t too hard to peak through the rim and see what your pad thickness is, at least front side, and I check them again every 5k when I’m rotating tires.

 

I'd say that, if the OP didn't know that it was the sensor wire, he should keep the sensor in place. Also, he should be aware that there's one on the left rear caliper as well.

 

Thanks everybody. Noticed the one on the back as well while I was changing out all 4 ABS sensors. One at the front is almost broken in half which is why I posted question. How does car notify you when brakes need replaced..... indicator light?