Push brake pedal shorts lights

[Highwaystar]

When I Step on brake pedal it draws on alternator, lights dim, etc. I disconnected plug (6wire) at kick panel and it stopped. No short I could find other than the single blue wire that goes to gas sending unit. I unplugged it from tank, and solved the problem, but a test light coming from dash on blue wire is still dimly lit. Would this tell me the gas gauge is bad, or grounded?
Thanks for any help. Again this is a 70 RR, rallye dash.

 

[Rusty 72]

You have a wiring issue at your tail lights. The switch on the brake pedal completes the circuit. If you're seeing a large voltage draw when hitting the brake pedal, the current is flowing to more than just the brake light bulbs.