Heater

If you know anyone who works in a repair shop, this information is available through Alldata.com or Mitchell on Demand. Unfortunately, these are subscriber services. If you do not know any technicians, you can try a google search for an online service manual for your model. Someone may have posted it in pdf format. Also, your Chevrolet dealer MAY be willing to provide you with that information. That really depends on the individual dealer, and their attitude. Some may be willing to help, some may only want you to drop the car off for service. If you try the dealer, try the parts department, rather than service. The parts department has "exploded diagrams" to find parts and may let you look at them. Often those diagrams will show the information you are looking for.