Heater Fan on High on All Settings

[GoBucks!]

It's been very cold lately and I noticed that my heater blower only blows at a high speed, no matter which speed I select. The first three levels are all the same speed and relatively high, then level four is slightly higher.

Thoughts? I've read that if the blower motor resistor/controller is bad it will only blow at all when high is selected, but I get action on all speed levels, they're just all pretty high. Could it be a relay?

Thanks!

 

[GoBucks!]

Update: When driving yesterday and adjusting the temperature, the fan sped up and slowed down according to interior temp, almost like it was in Auto mode, but it wasn't. I had it on Lo (which is like the second highest fan speed due to my issue).

 

[BlackWorksInc]

Hmm... I can't remember if these units are pulse-width modulated or use a resistor. I do recall a few times I've had to replace the HVAC control unit on 4Runners for something similar though.

 

[GoBucks!]

Hmm... I can't remember if these units are pulse-width modulated or use a resistor. I do recall a few times I've had to replace the HVAC control unit on 4Runners for something similar though.

Well, it actually ended up fixing itself. I'm not sure if it was the cold or something else, but once the days warmed up a little, the fan started intermittently working on all speeds, and is now functioning normally. Let's hope it stays that way.

Thanks for the tip though! That will be the first place I start if/when it comes back.