N1: Check Speed Control Amplifier Signal

Access the speed control amplifier and measure the voltage on the Red/Yellow wire at the speed control amplifier connector with the connector connect. See WIRING DIAGRAMS  . Drive the vehicle. Turn the speed control switch ON. Accelerate the vehicle to over 30 mph (48 km/h). Depress the COAST/SET switch. Turn the speed control switch OFF. Is the voltage greater than 10 volts with the speed control set, and less than 1 volt with the speed control off? If yes, go to the next step. If no, replace speed control amplifier. See SPEED CONTROL AMPLIFIER  under REMOVAL & INSTALLATION.