donbrew

Set the right knob to heat/floor. When it is set to defrost the A/C runs with no indicator.

Do not push the recirculate button. That also turns the A/C on with no indicator.

Could be the fan just wore out. It is the fan not the heat that is not working.

I get the sense that you know nothing about auto electronics; if that is the case it would be best for you to seek a professional for anything past fuses and relays.

Jens2008chevyHHR

The red light above the temperature dial is on, not sure how to turn that off, have pushed on it but it does not go off, no I am not mechanically inclined - but my boyfriend is a Mechanic so he will check it out for me. just hope it is a simple fix.

donbrew

I have no idea what red light you mean.

Perhaps you could go to the trouble of downloading and reading the free Owner Manual linked in my sig?
https://www.chevyhhr.net/forums/gene...-manual-3074/?

Cat Man HHR

Dondrew do you have a schematic for how heat is routed into the cabin? Does the left heater knob maybe function with the BCM to do this?
And yes what is this red light?

donbrew

The left knob controls the blend door. Blending cold side and hot side. I does go through the BCM, mainly because it is PWM.

You asked; here is too much info.

Cat Man HHR

That's great.
But is there a color by number picture of it?
I don't have a GM manual that could show the parts break down or even a flow chart for troubleshooting.
Just trying to understand the logic of car functions incorporated with today's technology.
Older vehicles had a heater control valve along with a blend door.
"Man has a finite mine, but lives in an infinite world" Einstein.

Oldblue

Hmm red light above temp dial




I only see a light on the button centre , that indicates the A/C is on

donbrew

It would be easier to understand if you forget the BCM part and say it is a step motor.

Oldblue

Turn the right dial to floor and face, see if there’s any change.
It shouldn’t effect the fan at all the centre dial sets the fan speeds.
Relay, resistor, or fuses, if they are all ok then the fan has given up.

Jens2008chevyHHR

it is the fan that is the problem and it will come on if you bang just below the glove box, so I expect it needs replacing