94 Blazer Brakes Broken

[Jerome44]

94 Blazer with 105,000 on it.
ABS light comes on @ 8MPH (indicating problem which should show up in computer...but mechanic says there's nothing there).
ABS is currently not operating.
The BIG problem is everyday braking: "Normal" braking...slowing for any reason is fine...but emergency application, when a quick stab of pedal is required, the pedal barely moves! Truck continues on its way, taking much too much time to stop! The pedal feels just as it does when the engine is turned off. (Power brakes...so when there's no engine, no boost)...the pedal is hard and doesn't give. A boost problem has been suggested. All else is OK, pads, lines, shoes, etc.
Does this sound like the problem is indeed the vaccum boost?
Just would like some input and info to arm myself before taking it in for service, so that mech will know what to look for.
Thanks in advance!

[troubles789]

Check your vaccum lines leading to your brake power booster for cracks or even slipped off first.