Dave,

Yet another recommendation. The guages on my SDL would go to 0 when I stepped on the brake pedal. I removed all the relays ( around the fuse box), cleaned the pins, and re-inserted. This seems to have fixed the problem. Note, I pulled a silver relay that is a shade more to the center than the fusebox. It had a 10 amp blade type fuse on the top of it with a plastic cap. The fuse was loose in the metal knotches that held it.

This may not help but is quick and easy to try. Good luck.

Chuck