One modification I have done is added variable fan speed control for the heater / AC fan. Primarily allows you to slow it down so it is not so noisy. I re-purposed the instrument dimmer knob as the speed control with an appropriate potentiometer, so there is no extra knob that looks out of place. Simply splice the instrument light wires together so they get full power all the time. I don't have any photos of the mod, but here is where I got the speed controller:
https://store.qkits.com/dc-mot...-control-mxa067.html
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