another blower motor question...and torsion bars question

[jprather]

ok, so, i checked my blower motor resistor, even changed it.. but.. fan operates at at 1 speed, doesn't matter what position the fan switch is in, it blowers on high ( i think). is it a bad switch or in the blower motor?
any clue before i start tearing apart the wrong thing?

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sorry, hit the wrong button.. to continue.. what is the difference between the 318 torsion bars and the 400 torsion bars? are they interchangeable? would 318 bars support the 400 ? affect handling??

 

[mopar 3 B]

As to the first question I would like to know that myself. Any one have the power flow for the different fan speeds. The second your 318 bars will give a softer ride and the weight difference is really not that great. The difference in the bars vary from year to year. They are enterchangeable the difference is in the diameter of the bar. The larger the diameter the firmer the feel.

 

[jprather]

well, let me ask you this,, the 3 pronged plug , i assume is the feed from the switch.. if so i can check to see if power changes from prong to prong when i move the fan speed switch.. right.. or does it interrupt the the ground??

 

[mopar 3 B]

Depends upon if you have a/c or not. Voltage differences will only show at the resistor output to the blower and from what I take of it is created by putting voltage into the resistor at the various points. The FSM only show the points of connection and not the paths per switch locations. Can anyone help us out here?

 

[jprather]

just to be clear it IS an A/c car

 

[Coronet 14]

If you are getting heat I doubt it's the resistor. Sounds like it's a bad switch. Performance Graphics in Tallahassee Florida can rebuild the switch unit

 

[Cranky]

Not real sure if it makes a difference but in the more modern cars, the blower resister doesn't have anything to do with getting heat into the vehicle but is what controls the fan speeds. On the torsion bars, 318 bars are smaller than the ones that came in a big block car, They do interchange between B and E body cars. A body and C body are different lengths. If you have a big block car with PS and AC, you might not want to use the bars from a 318 car. An old racer's trick is to use /6 bars and crank them up to ride height and use the stored energy so the front end will lift faster when you hit the throttle but....you might want to control the quick lifting action with a slower acting (more rebound dampening) shock. If the front end comes up too quick, it will lift the tires and then land rather fast if the engine doesn't have the torque to keep the front end up and thus unloads the rear tires......

 

[mopar 3 B]

From what I have found on the vacuum a/c heat switch there are 2 power wires to the fan. If mine is working correctly one wire powers a/c and vent functions and the other heat and defrost. The fan switch can be completely removed for the system and the blower fan will run at max speed. By matter of reasoning the problem of no speed control would be the speed switch. If I have time tomorrow I will replace mine and see if it corrects my speed problems.

 

[moparmarks]

Unplug the harness at the switch. Take a hot jumper wire and test the circuits at the harness. Red is low, dark green is med and light green is high. If all speeds work then it is the switch that is bad. If fan motor doesn't change speed then you can do this test at the motor harness that plugs into the resistor. If fan changes speed while testing at it's harness then the resistor is bad. Resistors do go bad. If speed doesn't change then it is the motor that is bad.
On the 62-72 T-bars there are a few different sizes.
.86 225
.88 273, 318, 361, 383-2bbl, 400-2bbl
.90 340, 383-4bbl, 400-4bbl
.92 440, 426 Hemi

On my 72 Satellite I changed the .88 for .92 and it make quite a difference.

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Also all 62-72B and 70-4E take 41" T-bars and are interchangeable. There a right and left bar.

 

[jprather]

now you guys see why i LOVE this sight!! most places i would feel stupid asking these questions, but here i get a lot of information and positive feed back, i guess most of you remember learning your way around your first MOPAR. It can be a little overwhelming at times!

 

[Nacho-RT74]

just made a quick read, sorry, running to job.

without the lever blower switch plugged ( or with lever switch damaged ), the AC control switch drives the power to the low speed ( higher resistor ) by default. This power is spliced to lever switch ( input prong ) and lower speed resistor at the same time.

Then the blower lever switch changes the resistor to mid and high speeds resistors ( which are less ohms ), than even the low speed being still feeded, by Ohms law the power will be increased being a parallel resisitor circuit with less resistence.

Note... HEATER AND DEFF speeds, are not lever switch controled, they have their own speed sourced from CONTROL switch with a brown wire

 

[mopar 3 B]

They must have built them different south of the equator or I have just gotten lost. I have a high fan speed and am trying to get the lower speeds to work.

 

[Nacho-RT74]

something weird... My car is wired like diagrams show

 

[moparmarks]

They must have built them different south of the equator or I have just gotten lost. I have a high fan speed and am trying to get the lower speeds to work.

Have you checked the resistor?

 

[Kernel Sanders]

You didnt mention the year of your car other than posting in the 71-74... 72- are different length than the 73+ here is a chart of length and thicknesses which may help

 

[mopar 3 B]

Originally Posted by mopar 3 B
They must have built them different south of the equator or I have just gotten lost. I have a high fan speed and am trying to get the lower speeds to work.



Have you checked the resistor?
yes
The thermal switch had burnt because of a bad heater motor. To much resistance. Have also checked the entire wire harnes from the vac switch to the heater motor. My blower switch has 4 speeds and i am only getting HI & MId HI on the A/C side of the switch with the heat/defrost side disconnected at the resistor. Only HI everywhere the heat/defrost plugged in. It has been to cold and wet to work outside on this but I plan to check the blower switch per your earlier post.

 

[moparmarks]

I was just guessing that the OP had a 71/2 from looking at his picture.

 

[Nacho-RT74]

BTW, I'm still above the equator ;)

here is the diagram... and you can see how the A/C Control switch source to blower splices into the lever swicth AND the low speed resistor, making this speed work by defaul even with the blower lever switch disconected

Then the resistor block output and max speed from lever switch are also spliced into the output to blower at bulkhead since max speed is full output from lever switch. When max speed is selected, the power running to resistor block barelly affects the max output which is practically sourced straight from the control switch ( through the lever switch ). BUT NOT if the lever switch is not working ( damaged or disconnected )

71 shown, but the same of course for the rest with just the lever prongs disposition difference for 73/74

 

[mopar 3 B]

here is my wiring diagram

 

[Nacho-RT74]

thats not a 71/74 B body... that loooks closer to a 68/70, or 70s C bodies. 71/74 B bodies never got a ciclying swicth