The picture on the left is the circuit assembly that monitors the tach signal in order to limit the motor RPM if something goes wrong like if you miss a gear when shifting and mash the pedal down with the transmission in neutral. It has two trip points. The first trip point simply shorts out the speed control pot so it acts as if you've taken your foot completely off the accelerator pedal. It has about 400 RPM hysteresis and is adjustable as is the point at which it trips. The second trip point which is set a few hundred RPM higher than the first opens up the main contactor circuit as a fail safe. This trip point is latching and will stay tripped until the ignition key is turned off and then on again. I used spare relay contacts wired to the original indicator light on the dash that reads "Check Engine" when either of the limit points have been hit. Cute, huh?
The next picture shows the inside of what I call the EBOX. It's where the miscellaneous small electrical components reside and where many of the interconnections are made. The Kilovac main contactor is in the lower left with copper bars attached to it for connecting the smaller guage wires. To the right of the Kilovac is a relay wired to a single R5-20 receptacle that the Todd DC-DC converter is plugged into. The control logic connects the DC-DC to the pack voltage when the vehicle is in drive mode or when the charger is operating. Moving around counter-clockwise we next find the RPM limiter with the cover on top. I call it the REVOLIM1. Next around the corner is the small DC-DC converter that powers the E-meter and just below it, the E-meter's pre-scaler. In the upper right is another relay for the resistance heating element in the cab. There are two shunts near the top. The small one is in the battery pack circuit whose most negative lead attaches to the ride side of it and the large one is in the motor circuit which just loops into and out of the EBOX. These shunts will eventually be connected to interface circuits that will drive my custom guages on the dash. I've also left room in here for a small controller to drive the power steering motor.
The last picture shows how a micro switch was installed onto the existing heater controls. The light blue lever arm is moved by the temperature control lever. This arm pushes the micro switch when the temperature lever is on full low. Moving the temperature lever about 3/8" from full low will allow the heater relay to close provided the heater fan blower is running. This provides a safety interlock and also allows me to run just the blower for cooling when the temperature lever is full off.