Brake bias gauge problems?

[jsf74]

I bought a new set of brake bias gauges this spring and 4 races in they both didnt go back to zero even with everything disconnected. I replaced them and after a few races I have the same problem. I just have them t'd off the lines after the mc's. What is going on here.

[jsf74]

Yeah quickcar. The sent me a replacement set with no questions asked but now what. 4 bad gages or what? They start out working fine.