heat issues

[MidnightBlade]

in my truck, when i turn the heat on the only time it sounds like a fan is turning is on high, the rest of the time it is silent. eventually some heat will seap through but not much. i dont run it on high because it all sonds like it is ready to blow apart when i do. i got some kinda squeling going on and some clunks, but why wont my other 3 settings work?

 

[LCAM-01XA]

The noise is coming from either the blower motor bearings, or the squirrel-cage fan - the first you replace, the other can be cleaned. The loss of lower fan speeds is often due to damaged resistor pack assembly, follow the harness coming out of your blower motor and you will find its connector - the pack is held to the plenum with two screws, and IIRC costs like $25-30 to replace.

 

[franklin2]

Usually the thermal fuse on the resistor pack has opened up, causing the loss of the lower speeds. You can replace the resistor pack like was mentioned, or if the thermal unit is open, you can replace it 121C temperature thermal fuse. I did a search and this is one of the places that sell them.
http://www.mcmelectronics.com/product/THERMODISC-G4A01121C-/17-140

 

[MIDNIGHT RIDER]

Have you pulled the blower/fan and cleaned out all the leaves, sticks, and trash from around the fan ??

Also, clean out the heater-core box and kick-panels.

 

[LCAM-01XA]

Usually the thermal fuse on the resistor pack has opened up, causing the loss of the lower speeds. You can replace the resistor pack like was mentioned, or if the thermal unit is open, you can replace it 121C temperature thermal fuse. I did a search and this is one of the places that sell them.
http://www.mcmelectronics.com/product/THERMODISC-G4A01121C-/17-140

Is that the thing that looks like a diode or resistor that is placed in between the resistor coils? What exactly is its purpose?

 

[MidnightBlade]

Have you pulled the blower/fan and cleaned out all the leaves, sticks, and trash from around the fan ??

Also, clean out the heater-core box and kick-panels.

didnt do a thing yet, just getting some oppinions, wasnt worried about the noises as much as the speeds. as the speeds means something electrical that could possibly cause more problems

 

[88F350idi]

X2 on the resistor recommendation

 

[franklin2]

Is that the thing that looks like a diode or resistor that is placed in between the resistor coils? What exactly is its purpose?

I don't know what scenario the factory was thinking about when they installed it, but it's like a fuse, only it works on over temperature. Your coffee maker has one inside of it. I guess when you get a good leaf and debris fire going in there, it opens up and stops the fan? .

 

[LCAM-01XA]

But it only works with the lower fan speeds, not the top (direct feed/ground) one?

 

[87crewdually]

If you only have high and lost your lower speeds than it more than likely is the resistor which you can get at any autoparts store around $17. It's below the fan motor on the passenger side in the engine bay. 2 small screws and a plug. Here's a pic:

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