Ok guys,
I just returned from the garage and here is some more info.
The ignition switch is new. The blower motor is new. As near as I can tell, the heater is a factory unit, the deluxe model with the 4 controls on the dash. The heater switch is also new.
If I disconnect the wire at the blower motor the engine dies right away when you shut of the key. The wiring under the dash looks just like a new truck, no frayed wires or butt connectors, etc. The control resistor in the airway is good.
The only thing that I can say is the replacement heater motor has a ground wire that is connected to the body of the heater housing. The original did not have this wire. By the way, I jumpped a wire from this ground directly to the battery negative and same result.
I also connected a test light to the positive side of the coil and you can clearly tell that the light stays on longer with the fan switch on as compared to off.
This really has me stumpped. The blower does run at a high speed, like I assume it should and maybe it is generating the extra.
Ya got me.
