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So I'm finally digging into the electrics on my 74 and wanted to start with getting the ventilation system going again. The controller on the console is seized up and I've got some fried wires and melted connectors in the engine bay, I'm thinking on putting this off until fall or spring but would like some type of air flow for the hot days this summer. Is there any reason I can't just run 12v power to the blower motor, ground it out and splice a variable voltage controller somewhere in there so I can still turn it from Low to high speed from inside the cab?
Because DC motor speed is not controlled via voltage variation.
Originally Posted by Frogly
So I'm finally digging into the electrics on my 74 and wanted to start with getting the ventilation system going again. The controller on the console is seized up and I've got some fried wires and melted connectors in the engine bay, I'm thinking on putting this off until fall or spring but would like some type of air flow for the hot days this summer. Is there any reason I can't just run 12v power to the blower motor, ground it out and splice a variable voltage controller somewhere in there so I can still turn it from Low to high speed from inside the cab?
From: Loud, Raw and Dangerous 1968 327 4S in Southern California
Looking at this 1974 Willcox wiring diagram it does look like there is a heater resistor network controlled by the heater/AC fan speed switch in the center consol. Three speed level positions on the switch and three resistors that could be selected. Since there looks to be only two wires to the DC motor, it could be the type that can be controlled by voltage. You might be able to rig something up but might be more effort that just fixing up what you have.
Good points about the resistors, but if just wanting to get by until after the summer, then it's a lot easier (and relatively cheap) to install a PWM which would be much more wonderful anyway.
Thanks everyone, I'm going to try a PWM switch and see what happens. I know once I dive in to getting the original setup going I'm going to end up with a larger project than I thought. Right now the Day's are too nice to let her sit in the garage.
Variable Voltage Regulator on Blower Motor
