I just bought an 89 245 and the brake failure light is on very dim and other times not at all. Any ideas what this might be?

Dear Doctor
Replace the bulbs first with the correct and matched quality. I had a problem when I cheaped out an bought bulbs that were the right volts and shape but the didn't say what the amps were( I didn't know it would matter) I believe an imbalance in the two sides of lights creates the warning light. I also had to improve the connections with solder on a friends 1980. Loose connections and mismatched bulbs turned out to be the problem here too.
Stephen

That light indicates any kind of light failure, not just brake lights. You have a grounding problem somewhere. Assuming it only lights up when you step on the brakes, I can think of two things:

1) Some grunge on the bulb contacts. Clean them off with fine sandpaper, then put some bulb grease on them and reinstall.

2) If that doesn't work, it could be a casing on one of the wires running through the ceiling and over the rear hinges has dried out, cracked and is grounding out. The only way to trouble shoot this is finding the culprit and wrap it with electrical tape.

Good Luck!

One of the Zero Mile maintenance items is to flush the brake system. This would require not only enough DOT4 brake fluid, but a complete bleeding done according to Haynes or Bentley.

Then you will find if you have a leak in the junction block. If one side does have a leak, you will notice the level in one of the MC reservoirs dropping (keep it topped up) and some brake fluid drops on the ground just inside the LF wheel.

Such a leak is one of the causes of brake failure light coming one. The light is triggered by a switch in the junction block that detects a difference in the pressure between the two brake circuits. Repair is done by removing the block and either replacing the O-rings in it or installing a new J-block.

Good Luck,

Bob

:>)