I let the fluid in the front brake fluid reservoir (furthest from the firewall) run low on my '99 Blazer. I filled the reservoir and checked for leaks. I didn't see anything noticable, but haven't done a good close-up inspection yet. I'll be driving my Sierra for a couple of days, so I plan to do the good inspection over the weekend.

The warning light had come on while I was driving and since I was driving on country roads with plenty of room to stop had I needed the e-brake, I just drove the 2 miles home. By the time I stopped in the driveway, the warning light was continuously on. I filled the reservoir and could see then that it was the front.

Two questions:
1. Does the front reservoir feed the rear or the front brakes?
2. What do I need to do to get the brake pressure differential switch to normalize.

I'll probably be doing the work by myself, so hopefully there's a easy solution.

 

the reservoir closest to the firewall feeds the front brakes and the one closest to the rad feeds the rear brakes.

fix the leak, bleed brakes, top up fluid,
it should fix it self after the leak has been repaired