Brake light on instrument panel...

[TUTONE]

1990 Chevy Suburban V1500 5.7L 4x4
The brake/e-brake light on the instrument panel used to blink what I think is a code (7 short - 1 long - 7 short etc.) I just had the tranny rebuilt and now the light stays on continuously. I'm thinking something to do with the RWAL. Any thoughts?

Thanks

[unplugged]

Low brake fluid? Yeah, I know a little too obvious, but worth a mention. Are the brakes working OK?

[TUTONE]

Fluid is full. I haven't ever had to add fluid except after bleeding of course. I've bled the brake lines at least twice. The brakes seem to be working fine except there's no rear wheel anti-lock like there should be. The brakes don't stick but the pass. side rear does grab sometimes. Just changed pads on the front and shoes on the rear last summer. I'm afraid it may be a messed up proportioning valve or something up near the master cylinder.