HVAC blower changes speeds on its own

[d3ktrix]

Hey guys,

The HVAC blower in my 2010 SS sometimes changes speeds on its own. Like a kid is playing with the fan speed knob and is twisting it up and down spasticly.

It doesn't anyways happen, but its frequent.
It used to only happen when the fan speed knob was at about 25%, now it seems to happen at all speeds and is getting progressively worse.
I've been noticing it for over a year now.

The fan doesn't have the common problem of making noises or clicking, yet.

Thanks

[xtreme industries]

I am experiencing the same issue with my 2010 2LT RS. let us know if you find out what it is.

[d3ktrix]

Will do.

[Gee]

Our early model Camaros both V6 and SS are known to have bad fans and heater cores. Your fan is just probably about to go or some wiring is loose.

[Low Saturn]

Mine has been doing this since I bought it. Took it in a few times and they did a software update to the HVAC controls that did nothing. I've checked voltage at the fan and it fluctuates. So its not the fan since its receiving variations in voltage. Mine also reverts back to full heat when the car is turned off. So when I get back in the car and start it, you can feel heat coming from the vents. I have to turn the system on, turn the knob from full cold air to full heat and back to full cold, turn on the A/C, let the air from the vents cool down, then turn HVAC system off.

I have a feeling its an issue with the controls.

[d3ktrix]

Originally Posted by Low Saturn

Mine has been doing this since I bought it. Took it in a few times and they did a software update to the HVAC controls that did nothing. I've checked voltage at the fan and it fluctuates. So its not the fan since its receiving variations in voltage. Mine also reverts back to full heat when the car is turned off. So when I get back in the car and start it, you can feel heat coming from the vents. I have to turn the system on, turn the knob from full cold air to full heat and back to full cold, turn on the A/C, let the air from the vents cool down, then turn HVAC system off.

I have a feeling its an issue with the controls.

Have you checked to see if the voltage fluctuates anywhere else in the car besides at the fan connector?
I haven't done any testing but my hunch always has been the fan speed knob is defective.
Mine has never got stuck on full heat.

[JamesMyBoy]

Not sure what the internals looks like on our fan speed knobs, but I'd try cycling it from one end to the other a dozen times or so. Back in the days of simple rheostats, corrosion would eventually build up on the wiper, and an occasional cycling over the full range on the knob would 'clean' things up a little. I still have an old radio that I need to clean up the volume control this way once in awhile.
Might be worth a try?

[d3ktrix]

Originally Posted by JamesMyBoy

Not sure what the internals looks like on our fan speed knobs, but I'd try cycling it from one end to the other a dozen times or so. Back in the days of simple rheostats, corrosion would eventually build up on the wiper, and an occasional cycling over the full range on the knob would 'clean' things up a little. I still have an old radio that I need to clean up the volume control this way once in awhile.
Might be worth a try?

I tried this today. I'll let you know if makes any difference over the next few days.
In my experience rheostats have always had a firm stiff feel. The Camaro controls are very free moving so I'm guessing they are digital. But we will see if it still has the same effect.

[Low Saturn]

The knobs have metal terminals that drag along small square contacts on the PC board that have a small gap between them.

[d3ktrix]

Originally Posted by Low Saturn

The knobs have metal terminals that drag along small square contacts on the PC board that have a small gap between them.

Had a feeling. Thanks for clearing that up