Re: Red "brake" light always on
Not sure on a 92, but on a 590-69 MK2, it's dual mode.....either the e-brake switch isn't all the way in or the fluid is low, the second part can be compounded by a sunk float.
I am guessing there is a fluid level sensor in the reservoir of the brake master cylinder.
FIRST, check the fluid level.
If okay, find and unplug the sensor for a test.
If the light stays out, and fluid is full, the sensor is bad.
If that doesn't do it, check the e-brake by locating and unplugging the switch.
If THAT doesn't do it, a differential proportioning valve may be the culprit.
If you lost pressure in eithr front or back system at any point and the shuttle stuck over....find the valve, "H" shaped with a single-wire switch in the middle. Unplug it and try that.