Q: I cannot get my DE40 to run, it will do nothing? Batteries are good.

According to Roger:

Assuming your batteries are indeed good with a pack open circuit voltage Assuming your batteries are indeed good with a pack open circuit voltage of 38 volts or nominal 36 volts, we first must determine what the solenoids are doing. Keep in mind this particular car (DE40) is wired differently than other systems. The solenoids are wired system negative in series through the B solenoid. That means that an open anywhere in the B circuit will prevent all solenoids from activation.

Notice in this diagram that battery positive is applied to the forward solenoid power terminal. From this terminal, battery positive is applied to the key switch. By selecting either forward or reverse, positive is then applied to the appropriate solenoid.

For example, let's say we have selected reverse. Positive is then applied through the green wire to the reverse solenoid. Positive now travels through the solenoid coil winding and out the white wire to the forward connection. It will then continue on through the accelerator switch and to solenoid B. Positive will then flow through the solenoid B coil windings and out to battery negative (black wire).

Think of the solenoids being in series like a string of Christmas tree lights. If the B solenoid is open, the other solenoids cannot activate. If the accelerator switch is open, the solenoids cannot activate. If the forward solenoid is open, reverse will activate when selected. If the reverse solenoid is open, forward will activate when selected. This information will get you started, if you need further assistance let me know.