Hi, thank you for looking at my post. My old contactor has 2 sets of 2 posts on one side (see picture http://www.arnoldservice.com/burnt%20contactor.jpg ) and my new contactor has 2 posts on opposite sides of the contactor (see picture http://images.grainger.com/images/products/5B133.JPG ). My question, referring to the first picture, is where will the light blue and yellow wires will go on the new contactor. Thank you for your time.

The wires you are talking about are for low voltage. The are the wires that activate the contactor as controlled by the thermostat.

The two tabs on the left side of the new unit pictured are the 24 volt connections for the new contactor. They are placed side by side.

Thanks! It is working now.

Good deal. Glad you got it going