Switch question for rear defroster

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Guess we must have been writing at near the same time....

I have never seen a rear defroster in person for an abody cuda. Must be pretty rare.
 
Guess we must have been writing at near the same time....

I have never seen a rear defroster in person for an abody cuda. Must be pretty rare.
The one I pictured with the resistor is for a later model Mopar.
 
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I can get you a resistance for the dropping resistor. BRB.


Toolmanmike- that looks like a rear defroster blower for like a Duster or 72 Dart.
Is that the one from the kit you have? Ideally that is the one you would want but the blower “shell” is larger than the two I have from my kits from 66’. Mine is a single wire and the blower motor (same sized) and the housing is smaller to fit the 66 spot above the wheel well passenger side. I figured the resistor is in line or mounts inside the steel opening. I figure what ever the low vs high speed difference is... no judge will know the speed unless they bring out a radar gun. Lol! As long as it “sounds “ different I am good.
 
Toolmanmike- that looks like a rear defroster blower for like a Duster or 72 Dart.
Is that the one from the kit you have? Ideally that is the one you would want but the blower “shell” is larger than the two I have from my kits from 66’. Mine is a single wire and the blower motor (same sized) and the housing is smaller to fit the 66 spot above the wheel well passenger side. I figured the resistor is in line or mounts inside the steel opening. I figure what ever the low vs high speed difference is... no judge will know the speed unless they bring out a radar gun. Lol! As long as it “sounds “ different I am good.
The one I pictured is from a partial kit I bought years ago. I have the blower and the speaker adapters. No wiring (I don't think) and no switch. I don't know what it came out of and yes the resistor screws into the blower housing. I wonder if the motors are similar size and mounting?
 
JC Whitney sells those. Not sure if the motor pulls enough amps to lower the voltage to make a difference. bUT a ballest resistor creates heat to drop voltage. Not hot enough to damage but I’m going to try that route first before since I have 1/2 dozen in the shop. Thank you for the Info. Different way to look at it.
Joe

LOL the resistor does not drop voltage by creating heat, unless you simply mis-stated. Heat is "the effect" from the current through it. All resistors work similar, Again, "ohm's law." CURRENT is what causes voltage drop. If you take a given resistor and draw very little current (a small lamp, etc) you will get very little voltage drop. A resistor with NO load other than a multimeter .........which draws a tiny amount of current will give you zero measurable voltage drop. A larger lamp or motor, etc will give more.

Heat is a side effect. The energy........that is the voltage drop.......must be converted into something, it simply cannot disappear, so the resistor radiates heat caused by the current through it.

But there ARE differences, which is why ignition resistors for Mopars are called a BALLAST. A ballast resistor CHANGES resistance with the amount of current going through it. Some resistors have more of an effect due to temperature than others, all resistors pretty much do change resistance with current, but a ballast does this by design.

As the current "tries" (and does) rise through a ballast, it heats up, which causes it to try to flow LESS current, thus attempting to "average out" current flow
 
On my 69 the motor only has one terminal and the switch is a OFF/ON/ON switch.
The cable is a special cable with two wires that are spliced together just before the motor.
The way this work is that one of the wires is not normal wire and has greater resistance so the motor runs slow, switch to the other wire and the motor runs normal.


Alan
 
Just found this thread with some good photos of mounting. I took some photos of the early Barracuda versus late defroster Motors and blower cages. The motors are the same diameter and the mounting flange is the same but the newer motor is 1/4" taller. The bases are a different speaker size and the thickness of the speaker adapter is different with the newer ine being slightly thicker. I also noticed that the blower cage where it mounts to the speaker adapter has a different shaped bolt circle between the two. Here's that link to the other thread: 1965 Barracuda rear defogger
 
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Thank you, that’s cool stuff.

Started to read the post you sent and I’m on it loooking for info back then. Lol!
 
Hey all,

Thanks for the info, I have more work to do to figure out what my plan is for my rear defrost addon. Where did everyone add their switch? Where was the OEM location and what switch was used if you added this feature?

Thanks in advance for the knowledge
 
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