THANK YOU. As suggested in this forum to prevent "frying" the ACC control unit as a result of the Recirculating Pump aka Auxilliary Water Pump has seized or shorted or demands greater than 1.3 amps to operate, I have installed an in-line fuse with 1.0 amp fuse on the Hot line by splicing a connection about 2" from the connector. In my 84 300DT, using a circuit tester with the ignition on ON position (engine not running); ACC on defrost; power to the pump disconnected, the brown wire with red dotted line is the power.

All is well!!