Heater fan doesn't work - 1971 Plymouth Fury III

[BE_Fury]

I have a 1971 Fury III with AC - ac not currently installed - in which the Blower Motor doesn't work.

The fan wheel was broken. Therefore the Blower Motor was removed. I got a used Blower motor with a Fanwheel. I installed this. Unfortunately, it doesn't turn on when I switch on the control panel accordingly. Motor works when I jumper to + the battery. I replaced the switch and heating resistor with (supposedly) working ones.

How do I get the fan to run? Does anyone have a good tip?

 

[Leviathan]

Did you replace the switched 12 vdc connector back onto the heater module, it's above the terminal with the light green wire difficult to see.

 

[live4theking]

This might not be the case on a 71, but in 68's the fan will not run unless one of the heat/ac buttons is pushed in.

 

[CBODY67]

If the blower motor resistor was flaky, there would be evidence of that on the resistor assy and its connectors. As to "heat colors" or broken resistor wires.

CBODY67

 

[BE_Fury]

Did you replace the switched 12 vdc connector back onto the heater module, it's above the terminal with the light green wire difficult to see.

Yes, I’ve replaced it.

This might not be the case on a 71, but in 68's the fan will not run unless one of the heat/ac buttons is pushed in.

I tried it out of sheer desperation, but it didn't work…

If the blower motor resistor was flaky, there would be evidence of that on the resistor assy and its connectors. As to "heat colors" or broken resistor wires.

CBODY67

They are apparently fine

 

[3C's & a D?]

Looks like the resistor has seen some pretty good heat. The longest spring (full on?) seems to have melted a bit into the board. There may be a loose connection underneath.

Great pictures!

 

[Big_John]

Does anyone have a good tip?

Here's my tip... Buy a test light or a multimeter and start figuring out where there's power and where there isn't.

Also, the blower motor resistor is only used when you're running the slower speeds. The blower will still work in the high position with a bad resistor.

If this is the "replacement" blower switch, you can start checking there. It looks like it's been sitting outside. You can find those new with a little looking.

 

[BE_Fury]

I tested all lines with a tester. A signal comes from the blower motor to the switch and to the heater resistor. Where does the electricity come from? I couldn't detect any tension here.

Blower Motor to Inside

Heater Resistor