I'm putting a pre-'91.5 cab on my '92 frame. On the older cab, there is a "box" with wires coming out of it, mounted to the firewall, about 6 inches under where the clutch master cylinder mounts. It has factory-looking weather-pack connectors. What is this box? It is not on my '92 cab.

I have been trying to get the electricals to match up....when i turn the key, the gauges move, and the message center goes through its paces, but i cannot crank-i think this is because the computer is still looking for a signal that the auto trans is in park, even though the auto is gone. Right now i still have both the '91 and '92 harnesses laying in the engine compartment, trying to figure out what to hook up to make stuff work. Any tips?

 

did you hook up the clutch lock out? no starting without the clutch pushed

 

The box is the grid heater control module used on pre 91.5 trucks.

 

fantastic, thanks for filling me in