brake pressure switch on 1990 GMC Suburban 1500

The brake service light stays on all of the time. Is this an indication of a bad pressure switch? I notice that there is a "port" on either side of the pressure switch, what are these for?

Asked by for the 1990 GMC Suburban 1500
1 answer 1 comment
First, check your brake fluid level, if it is low that will set the light. If the fluid level is ok, then it can be several things. Have a good shop Diagnose this issue to be safe.

here are some shops
if you dont know , dont mess with it. too many people kill others thinking they know how to fix critical systems.. besides you'll live longer if you do take it to a real break shop or the dealer..