the fan on my rear a/c will not work on the first 2 speeds. works fine on 3 and 4 , but nothing comes out on the first two. Is this a relay/fuse issue or am I looking at new motor?

 

I am not an expert. But on my Ford Escape this was a "blower motor resistor". The dealership wanted $200+ to replace it. I bought it online for $18 and it took me 15 minutes. Now again, that was in my Escape so I don't know where it is on a suburban. But you may want to look for a Blower Motor Resistor for the 2004 Suburban.