Heater defroster power

[D Stand]

Yesterday I was working on the wiring and when I got to the heater I noticed a pre-wired 30 amp breaker on the power lead. The RT wiring harness only has a 20 amp fuse and a smaller wire feeding the heater. Has anyone blown the 20 amp fuse? I feel like cutting the 30 amp out since the 20 should pop first but hoping to here your advise. Maybe I need to re-wire to utilize the 30?.

Thanks Dale

[JasoninAZ]

You will want to keep that 30 amp breaker as the main power to the blower motor. The heater/defrost wire coming out of the harness is meant to power the heater controls. Hope this helps.

[BEAR-AvHistory]

Have never checked the fuses after installation so can't be sure what the amperage is. Do have the RF harness, fuses & FFR supplied heater. Five winters on it with no blown fuses. Car goes out most days above 40*F so the heater does get a workout.

[D Stand]

JasoninAZ - there is only the one wire to hook up for power with the 30 amp breaker. No other for just controls.

Has anyone checked to see how much the blower actually draws? Is the 20amp fused wire from RT harness for a different heater than supplied by FFR?

[boat737]

I had the same question 4 years ago. https://thefactoryfiveforum.com/showthread.php?20881-Vintage-Air-Heater-wiring-question
I ended up cutting out the 30 amp breaker, and just using the 20 Amp RF circuit. So far, no problems with the 20 Amp fuse.
Here's some more of my heater note's if you're interested. https://thefactoryfiveforum.com/showthread.php?20883-Vintage-Air-mounting-modification

[D Stand]

Thanks much for all the details Boat 737. I know what to do now. Love the shroud you made!