brake light and abs light on

Hi Guys,
Got a 93 Chevy G20 van 141,000 mi. and the ABS and red brake light both on, the ABS came on first, then the red brake light, I checked the brake fluid for the red brake light and the small reservoir was empty, so I filled it and the red brake light is still on, could it be the parking brake switch causing the red brake light to stay on, brakes are fine stops great, a little pulsing in the pedal, probally warped rotor disks causing that. I am also in need of an owners manual, or at least the fuse diagram, mine did not have a manual when I bought it
Any ideas, anyone???

Yellow light is a ABS problem.
Red light is usually regular brake problem.
If it was out of brake fluid you have a leak.
Check and Clear ABS codes and see what comes back.
Does the master cylinder have a low fluid sensor?
If so unplug it and see if red light goes out.
Step on e brake and see if light gets brighter.
If so the e brake switch is working good.
Let us know what the upper test do and show.