Anyone have any idea why my HVAC's blower motor will only operate on fan speed 3?

 

I thought that if the blower motor's resistor pack failed, it would only work on fan speed 4...

The speed selector switch has failed.

 

You are correct on the "High Only" if it was the resistor pack.

I bought a replacement from Oreily with a lifetime warranty for $40.

 

I was able to partially repair the broken one by cutting and resoldering the broken coils but ultimately the new one ended up being a better deal.

 

I also thought about cannabalizing a resistor pack on to the damaged one with a part from the junkyard from a more reliable set of resistor coils or some cheap aftermarket coils but again the $40 part with lifetime warranty was too good a deal. 

 

It is nice to have the multiple speeds particularly for the defroster. The coil pack is on the passenger side below the glove box and has three (?) screws. Pretty easy to change but I did have to get in a weird position on the seat to get at it. Pretty easy to get out and at least inspect and check the coils for resistance.

Edited March 14, 20179 yr by kmpdx

You can get a PWM 15 amp variable speed controler on Amazon for about $15 and have full solid state variable speed control.

 

GD

I've got an EA81 (for the failed resistor pack in the T-wagon) and an EA82 resistor pack on the way to my local dealer.  I'll see if I can get a fan speed switch too.

 

Thanks!

same issue here (except fan speed 2) - folks said clean or replace the switch. 

https://www.amazon.com/RioRandTM-Upgraded-6V-90V-Motor-Controller/dp/B00F839VNQ/ref=sr_1_3?ie=UTF8&qid=1489590415&sr=8-3&keywords=pwm+motor+15a

 

GD

GD,

That is awesome. Have you installed one like this? Where do you mount the board? 

I have used one recently on a Chevy Astro where the resistor coil pack was unobtainable. Worked great. You can mount it in a duct if you want but we didn't. Doesn't seem to be an issue so far.

 

GD