Q: Brakes go all the way to floor w/o stopping.Warning light comes on. on 1995 GMC Jimmy

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Brakes have been acting strange lately.Yesterday went completely out.Warning light came on.Recently purchased w/less than 50k miles.Unsure of how to check fluids (no manual).Tried googling w/too many results on everything but location of fluid chamber.
(1) Answer
(1) Comments
When you open your hood,standing in front of your truck on the right
against the firewall you will see your master cylinder which has
brake lines coming out the side.

The cover snaps off lifting the side tabs to open the cover.
If the brake fluid is down,add fluid and make sure rubber seal is
on cover first and then tap the edges of the cover down till it seals.

Pump brakes several times while it's running and look under vehicle
to see if there are any leaks.If the truck is originally from texas,it could be
a wheel cylinder,brake hose or front caliper leaking.