ABS codes 93 Astro

GA_googleFillSlot("Forums_ROS_300x250_noad");I have a 1993 Astro (290000km) vin "W", Central Multi-port Fuel Injection (CMFI). It has a Kelsey-Hayes 4WAL anti lock braking system.

I have checked my codes for the ABS and the following codes appear:

81 Brake switch circuit shorted or open
86 Shorted anti-lock warning lamp
12 System Normal

Here is a link of the codes and the reader that I used.

My question is what do these codes mean and how can I test, then repair the problem?

Thank you in advance.

Morrell

Sorry, I don't have any early M/L body ABS diagrams. If the code definitions are correct, I'd be looking at the brake pedal switch and instrument cluster lamp, and their circuits.