I don't know my model number of my suburban but we also bought and replaced and cleaned up heater and it turned out to be only a loose connection several years ago. Found it by wiggling wires. Took some time. Wiggled one wire out of many and then heard a "click" on one wire. Removed that wire connection and it was rusty, cleaned and it worked right after that for about 3 months and did it again. Turns out that connection was also rusty inside the motor. Cleaned it up (actually RV guy took motor apart and cleaned up connections inside motor) and no problems since. Took a long time to find. First time thru was quick to check wires, second time thru, checking wires and use volt meter to make sure elec was making it to connection took a lot longer to wait for system to get into right operating step. I was able to use a paper clip to "jump" 12 volt and put a meter on it. Hope this helps, I'm not a elec guy but I can tell if something has a connection or not. It would also be nice to have a troubling shooting guide or owners manual handy. Not sure if link will work or not I just googled it up.
http://www.brwholesale.com/itemNotes/schematics/Suburban/Furnaces/Furnace_Service_Manual.pdf
