ABS failure on 1991 Mercury Cougar

I have an XR7 and the other day my anti-lock and brake warning lights came on on the cluster, the brakes still somewhat work yet they are manual now. I have no electric assist in them. Could this be the ABS brain or the connection or.....? Ijust want to know what i'm looking for before I have to get it diagnosed if I can't figure out what the problem is.
Thanks

Asked by for the 1991 Mercury Cougar
Without a machine to diagnose the problem there's no way of finding out whats wrong unless you have a leak somewhere or the ABS light is flashing the codes.
2 answers
You might have a problem with the brake booster, depending on the year you might have a hydralic brake booster and not a vacuum brake booster. The nitrogen filled sphere looses it's charge anf the pedal goes hard.