The brake light in my 1989 Chevy 1500 P.U. blinks 6 times then stays lit?

It's the rear anti-lock brake module/ecu flashing a trouble code 7. We just had 1 in our shop with a code 6. Replacing the vehicle speed sensor on the transmission fixed it on ours.

For the brake light, the long flash gets counted with the short flashes. So 1 long flash and 6 short flashes is actually a 7. (if this was the check engine light, that would be a code 16)

Code 7 is for: Shorted isolation valve or bad ECU. The brake ECU is bolted on the side of the master cylinder. The isolation valve is under the master cylinder and has brake lines plumbed to it and has 2 wires going to it. Not to be confused with the regular proportioning valve that's in between the 2 and has 1 wire and looks like any other proportioning valve.

This is an extremely primitive ABS system.It doesn't even have wheel sensors. Pulling the 'brake' fuse under the dash or disconnecting the battery will clear codes.

Get the service manual for your exact truck.

Read in the brake section for such a symptom.

Maybe you can look at the wiring diagram and see exactly what is connected to the dashboard brake light?

Maybe it means something.

Maybe you have some random problem.

The fact that it blinks exactly 6 times, every time, is strange.

I am very familiar with Chevrolet cars, but never heard of this before.

You can always call a GM dealer and ask them if the truck needs service?

I always send people's car problems to the local high school auto shop.

They usually check things for free and repair for the cost of the parts.

Check it out.

Check the connections to the parking brake and the porportioning block for shorts.