I have a '53 truck, 12 volt system, with original recirc. heater. Last winter I burned out the original 6 volt heater motor, and installed a new 12 volt motor from Chevy Duty. Now, this thing barely puts out any heat. It seems like the motor is just not spinning fast enough to move a sufficient amount of air. I've ruled out the switch by wiring the heater directly to power via a 110 volt household switch. The result is that when the temperature is much below freezing my heater can't keep the cab comfortable, and the defrost is totally lame. So, has anybody experienced this with replacment heater motors, and is there any way to make the darn thing spin faster?
