Brand new speedo. I was rewiring my car so I ended up with just the speedo plugged into the receivers. I turned in on, went through the setup, everything was working fine, even the blinking light for the zero boost mode.

I plugged in the servo and the speed control light went out. I had no control over the speedo or servo. I unplugged the servo and the speedo light started blinking again and it would run the motor. Plugged the servo back in and it stopped. I tried a different receiver with the same results. I tried a different servo with the same results. I went back to my old speedo and the receiver and servo work fine.

Any ideas?