I bought a 2007 HHR and the cruise doesn't engage. The light comes on in the steering wheel but will not hold the speed, anything I can check myself before taking it to the dealer?

 

Welcome to the site.

1st thing. Check all your brake lights. The cruise control electrical system runs through the brakelighting circuit. A burned out bulb will not allow the cruise control circuit to operate.

 

Are one of the two switches at the brake pedal for cancelling the cruise?

 

Sort of.
the computer actually senses the light bulb resistance, If a bulb is out the cruise will not engage.

 

I had this issue a few months ago and found one of the switches mentioned above had actually slipped and was not making proper contact since the little plunger was not hitting the stop. This was due to the bracket holding the switches had twisted slightly making the switch out of line. I replaced the switches anyways as they are cheap (Rockauto.com) and made sure they lined up. The alignment issue is a bugger to see, especially for an old guy like me!

 

Hidden CEL codes can prevent the cruise from operating also.

 

And if your HHR is a five speed, there is another cruise disabling switch on the clutch pedal.

 

I drove the car today and kept trying to get the cruise to come on, and lo and behold when I used my boot to lift up on the brake pedal with a lot of force, the cruise actually engaged. If I let up on the pressure I was exerting just a fraction, then it disengaged. It is definitely in those switches or the alignment. Thanks for the hint.

 

Adjusted the switches and everything is working fine, as far as the cruise control is concerned.

 

Awesome, glad to see the issue is addressed and repaired.